Ethereum is the OG smart contract platform, but Solana took the mindshare after some scalability stumbles by Ethereum and a few disproportionately successful speculation apps on Solana like pump fun.
Pre-2015, Ethereum was the only game in town and you could build anything from casinos to trading platforms on Ethereum. But then, CryptoKitties showed how gas can be brutal on the mainnet (yes, everyone was trading and breeding digital cats back then) with $50 transactions. Ethereum moved to layer-2 architecture but that caused fragmentation as each L2 became its own walled garden. Enter Solana.
Solana said - what if we just made the main chain faster and keep scaling horizontally? Controversial idea because it doesn't work in theory but seems to work in practice. Solana picked speed over everything, including decentralization.
Ethereum has the history and the ecosystem. Solana has the speed and the momentum. Neither is going away. Let's look at how they are performing over a rolling 1 year timeframe. See also and check out detailed risk-return analysis at gale.finance and gale.finance/compare/eth-vs-sol