This paper examines the impact of protocol-level innovation in blockchain on user engagement across decentralized platforms. We explore the Ethereum Merge, a major technical upgrade that transitioned Ethereum from a Proof-of-Work to a Proof-of-Stake consensus mechanism, and its impact on EVM-compatible platforms and Layer 2 solutions built on top of Ethereum. We employ the Difference-in-Differences (DID) and Synthetic Difference-in-Differences (SDID) methodology to identify the causal effects. Our results highlight that protocol-level innovation can produce heterogeneous effects across the blockchain ecosystem, with platforms that are structurally closer to Ethereum benefiting more from the Merge.