Rollups scale Ethereum, but the real challenge is how to connect them

The blockchain infrastructure of 2025 has reached a turning point reminiscent of the "pre-internet era." During that phase, the internet was growing rapidly but faced new bottlenecks due to non-standardized protocols and a lack of communication between networks. Ethereum's current situation is quite similar; the rapid expansion of the Rollup system has made it feasible for mainstream applications to go on-chain, but at the same time, a more fragmented chain layout, higher development and maintenance costs, and a disjointed cross-chain experience are quickly eroding the benefits brought by scaling.

The growth of the RaaS (Rollup-as-a-Service) market reflects this contradiction. Between 2024 and 2025, the global RaaS market size continued to expand from $1.12 billion, with a compound annual growth rate exceeding 29%, and the Asia-Pacific region even surpassing 30% growth. The data reflects not just a "hot track," but a structural change in scaling methods: self-built chains are giving way to standardized services, and the way Rollups are created is shifting from one-off engineering projects to industrialized mass-produced infrastructure. As a result, Web3 has moved from the "battle of a hundred chains" to a new stage of "systematization of infrastructure."

New Dilemmas After Scaling

The rapid increase in Rollups has been particularly evident over the past two years. Take Caldera as an example; the chains it serves have exceeded 60, covering 40 million independent wallets, over $550 million in TVL, and more than 1 billion cumulative on-chain transactions. Among the 160+ mainnet Rollups in the entire Ethereum ecosystem, the chains supported by Caldera account for more than a quarter. The driving factors are easy to understand: RaaS services have made chain development no longer reliant on specialized teams struggling for half a year; DA layers like Celestia and EigenDA have significantly reduced costs; and the maturity of frameworks like OP Stack, Arbitrum Orbit, zkSync, and Polygon zkEVM has transformed "deploying a well-performing chain" from a daunting task into an engineering option.

The shift from "impossible" to "too easy" has not led to seamless growth but rather to another form of systemic complexity. States and assets are scattered across their respective islands; infrastructure teams face redundant construction; developers must maintain code and compatibility across multiple chains; users are forced to jump, migrate, and deal with repeated onboarding across multiple chain environments. This scenario is very similar to the fragmented network landscape of the early 1990s internet: each network can operate, but there is a lack of "channels" between networks, making it impossible to build a truly scalable whole.

Connectivity is the Real Bottleneck

RaaS has reduced the cost of self-built Rollups from "almost prohibitive" to an acceptable range. What used to be a project involving consensus, DA, security, auditing, node operation, monitoring, and other multi-layered systems taking three to four months has now become a matter of choosing configuration options. However, the real challenge after Rollup scaling is that while Rollups have moved execution away from L1, they have not solved the connectivity issue "between Rollups."

Cross-chain still relies on L1 paths, which are slow, expensive, and unpredictable; bridges are either secure but have long wait times or fast but questionable in safety; developers can deploy multi-chain structures but cannot create a truly unified experience for "an application spanning multiple chains." This lack of interoperability is eroding the advantages of Rollups, even causing some teams to hesitate about "launching their own chains," not because the chains are bad, but because they feel too isolated. In simple terms, RaaS has brought "scaled expansion," but what follows is "scaled fragmentation." The next critical question for the industry has shifted from scaling to connectivity: how to enable more and more Rollups to collaborate with each other rather than isolate themselves?

Reorganizing the Entire Rollup World

A key perspective behind Caldera's development of Metalayer is that scaling is not the goal; collaboration is the ultimate infrastructure objective. After helping over 100 projects launch their chains, Caldera has realized one thing: launching a chain is easy, but making it thrive is the real challenge. The script after each new chain goes live is the same. Teams spend months on technology, the chain goes live, and then they find no wallet support, no applications willing to migrate, and no users coming in. You have to negotiate partnerships one by one, find ways to bring liquidity in. Technology accounts for only 20%; the remaining 80% is about "getting the ecosystem moving." The more realistic situation is that many teams find themselves stagnant three months after their chain goes live: daily active users in the low hundreds, TVL lingering in the six-figure dollar range, and only their team members posting in developer forums. This is not a technical issue but a systemic dilemma of ecological cold starts.

What Metalayer aims to do is eliminate this 80% of repetitive labor. It is not about creating another chain or a better cross-chain bridge. What it wants to create is a "connection layer," aiming to enable Rollups to interact as if they were on the same network. The key idea is: instead of having each chain build its own ecosystem, all chains share a common ecological foundation. How to achieve this? Three directions. Developers can directly call across chains when writing code, without needing to adapt for each chain individually. This means a DeFi protocol does not need to deploy once on ten chains but can deploy once and read liquidity data from all chains. When a new link is added, it automatically gains wallet support, asset liquidity, and application networks from the entire ecosystem, without starting from scratch to negotiate partnerships. It’s like joining an existing business alliance; you don’t need to sign contracts with every merchant; the moment you join, you automatically gain all the benefits. All participants benefit from network growth through $ERA, binding interests together. When the network's value grows, it is not just the platform that benefits; every contributor can receive corresponding rewards.

For users, the effect is: cross-chain operations go from "troublesome multi-step processes" to "just one click." There’s no need to worry about the paths taken, the bridges used, or potential wrapped asset issues. If you see an opportunity on Chain A and want to transfer assets from Chain B, previously you might have to open three websites, connect wallets twice, wait for several minutes, and worry about potential errors along the way. Now, you only need to confirm once, and the system takes care of the rest. This change in experience is what truly makes ordinary users willing to engage with a multi-chain ecosystem.

New Propositions After Scaling

Why is this time point worth paying attention to? Because Rollups have moved from the experimental stage to the infrastructure stage. The data is straightforward: L2 transaction volumes are already about 10 times that of the Ethereum mainnet, and since Ethereum shifted to a Rollup-centric roadmap in 2020, over $38.5 billion in value has been transferred to L2 and L3. The technical feasibility of scaling has already been proven. However, a new bottleneck has emerged; the growth rate of Rollups has exceeded their collaborative capacity limits. There are more and more chains, but their connectivity has not kept pace. This means the first wave of scaling benefits is being offset by fragmentation. The next wave of growth will not come from "more chains," but from "chains being able to work together like a network." Solutions like Metalayer are gaining attention not because they offer some novel technology, but because they fill a long-missing segment in the scaling roadmap: the connection layer. If Rollups are the road to Ethereum's scaling, then the connection layer is the interconnecting hub between roads, the true infrastructure that allows network scale to take effect.

Looking back at Ethereum's evolution, a clear trajectory can be seen. Layer 2 and Rollups moved computation off-chain, solving the "too slow" problem and significantly increasing throughput. RaaS platforms have standardized deployment, with Caldera helping teams deploy over 100 chains in two years, addressing the "difficulty of launching chains." But as launching chains becomes easier, ecosystems begin to fragment. Each chain operates independently but finds it hard to collaborate. This stage is now opening, and Caldera's launch of Metalayer represents a representative attempt at this stage: not to create another chain, but to provide a collaboration layer for the entire Rollup world. Cross-chain development becomes as simple as local development; new links gain wallet, liquidity, and application ecosystems immediately upon entry, and all participants benefit from network growth through a token mechanism. In terms of user experience, complex cross-chain operations are simplified to a single click; on the development side, a single deployment covers multiple chains. Just as the early internet needed the TCP/IP protocol to unleash network potential, the blockchain world also needs unified collaboration standards. Scaling has brought the industry to this point, and collaboration will take the industry further. This shift from "building more roads" to "connecting roads into a network" marks a new stage for the Ethereum ecosystem. And the exploration on this path has just begun.