The Ethereum scalability paradox: Why does bandwidth surpass latency?

In a recent intervention on X, Vitalik Buterin has proposed a provocative thesis that challenges common assumptions in the blockchain industry: prioritizing bandwidth expansion is fundamentally safer for Ethereum than pursuing aggressive latency reduction.

The Proven Path to Scalability

With the support of technologies like PeerDAS and ZKP, the Ethereum community has charted a clear route to achieve massive expansions. Theoretical projections point to a thousandfold increase relative to current capacity. Technical parameters improve significantly both before and after implementing these scalability solutions. From a purely physical perspective, there is no fundamental barrier preventing the combination of “extreme scale” with “robust decentralization.”

However, reality is different when it comes to latency. The limits imposed by the speed of light represent only part of the problem. Practical constraints are more suffocating: nodes must operate globally in rural areas, homes, and commercial establishments, not just in specialized data centers. Node operators, especially validators, require censorship resistance and guarantees of anonymity.

The Economic Dilemma of Decentralization

An uncomfortable question arises: if operating a staking node outside New York reduces yields by 10%, how long will it take before most validators migrate to major financial centers? This phenomenon would gradually degrade the true decentralization of the network.

Ethereum must pass the “abandonment test,” meaning the network cannot rely on continuous social coordination to maintain its distributed nature. Economic incentives must support most of the system, though they cannot shoulder all the responsibility.

Pragmatic Improvements Within Reach

Without making structural compromises, it is possible to moderately reduce latency. Advances in P2P networks, especially through erasure coding, can decrease message propagation times without requiring individual nodes to amplify their bandwidth. An optimized availability chain, with fewer validators per slot (512 instead of 30,000, equivalent to approximately 30,000 km in terms of traversable distance in a global network), can eliminate unnecessary aggregation stages.

These optimizations could achieve latency reductions between 3 and 6 times. Reaching thresholds of 2 to 4 seconds is entirely realistic within these margins.

The Fragmented Future of Applications

Ethereum is not a global gaming server; it is the settlement system of digital civilization. Applications requiring speeds faster than the “heartbeat of the network” must incorporate off-chain components. This reality guarantees that L2 will persist indefinitely, even if Ethereum achieves massive scalability. Other reasons include the flexibility of custom virtual machines and demands for even more radical scaling.

In the long term, artificial intelligence will inevitably generate “faster-than-heartbeat” applications. If an AI processes 1000 times faster than humans, its “subjective speed of light” is only 300 km/s, allowing almost instant communication within cities but not between intercontinental distances. This will push blockchains toward urban-scale, even building-level, all necessarily L2s.

Conversely, it is not pragmatic to incur astronomical costs to run validators on Mars. Ethereum remains rooted on Earth, serving both ultra-localized needs in cities and an unprecedented planetary scale.