Ethereum reaches a milestone in 2025. On-chain transaction volume and DeFi ecosystem market share both hit record highs, which should have been an opportunity for explosive mainnet revenue. But the reality is somewhat disheartening—the mainnet transaction fee income has instead plummeted.

The underlying data is quite interesting. Layer-2 networks generated approximately $129 million in revenue throughout the year, of which only $10 million flowed to the Ethereum mainnet for settlement and security. The remaining $119 million? All pocketed by Layer-2 operators. In other words, Ethereum has foregone over $100 million in potential revenue this year.

This reflects deeper issues of ecosystem fragmentation. While efficient Layer-2 solutions attract a large number of users and transactions, they directly weaken the mainnet's economic incentives. For Ethereum, this is the cost of scaling success—on-chain prosperity, but diluted mainnet revenue. How to balance ecosystem growth with its own incentives in the future may be a key question for the Ethereum ecosystem.