According to Vitalik Buterin, a significant challenge with enshrining execution fees within the Layer 1 (L1) protocol is the inability to reliably measure the fees on Layer 2 (L2). He compares this to a government trying to enforce sales tax by accessing the RAM of digital payment systems, highlighting the complexity and impracticality of such an approach.

According to Vitalik Buterin, there is significant interest among Layer 2 (L2) solutions to collaborate on improving interoperability within the Ethereum ecosystem. He also noted that Ethereum's Layer 1 (L1) has become more robust over the past year, despite challenges related to censorship and centralization.

According to Vitalik Buterin, Ethereum has seen significant improvements. Transaction fees on Layer 2 (L2) solutions are now below $0.01. Two Ethereum Virtual Machine (EVM) L2s, Optimism and Arbitrum, have reached stage 1. The user experience for cross-L2 wallets has greatly improved, eliminating the need for manual network switching. Additionally, Zero-Knowledge (ZK) tooling has become more powerful and mature, enhancing the overall ecosystem.

According to Vitalik Buterin, cross-L2 interoperability issues within the Ethereum ecosystem, including L1, rollups, validiums, and sidechains, will be resolved sooner than expected. He notes significant energy and determination to achieve a seamless user experience across these layers.