Most (not all) web3 games don't have a server. Just frontend interacting with a smart contract

And what do you think you're getting the frontend assets from? They certainly don't live on-chain, and usually aren't open source.

Yes I realize that could be an issue, but it's way easier to address than keeping a server alive. See: https://archive.org/details/softwarelibrary_flash_games

Distribution of binaries of obsolete games is a solved problem. It costs money to leave dedicated servers running for legacy titles, but costs nothing to leave the Steam page online. Plenty of commercial games are also free to download, but cost money to register and actually play.