I can see something like stadia working for someone who owns a playstation, doesn't want to build gaming PC, but wants to play a game that's not available on playstation.There's no such thing as a 2nd option to console or even space for whatever that is, they're buying one or the other, nobody's paying Google for the same games twice.
For example, I buy a ps5, but would also like to play something like outer worlds 2 without having to fork out cash for another console or a gaming pc for that one game, so a streaming service would be perfect in that scenario.
But I also dont see a strong enough market for that type of scenario to profit from it in any meaningful way.