Main differences between (current state of) Ethereum and Solana is that Solana is a cheap and performant blockchain while Ethereum is an infrastructure primitive that enables you to build literally any verifiable system including cheap and performant blockchains.

Cheeky but true. I believe we saw Sol run also due to nostalgic reasons, where it could've been literally anything, Aptos/Sei/Sui, etc.

There were and will be numerous of L1s but the most money and attention lie within the ETH ecosystem. And exactly due to that we have the ability to use ETH L1 as a settlement later.