Where is Web3 P2P? Decentraland is centralized. The Sandbox is centralized. OpenSea is centralized. Metamask is centralized. Bitcoin and Etherium mining depend on big server farms that are more centralized than Akamai.
But even if web3 was 100% decentralized it still would be an expensive inefficient P2P.
That just seem stupidly wasteful approach. I have nothing against actually p2p where everyone controls and runs the parts useful for them, even if there is some duplication. Think of Bittorrent. You don't download entire bittorrent network, but parts that you want...
now try that with your steam game.