Have you ever tried stadia? It's incredible 99.9% of the time. But that 0.1%... I thought I could put up with a few frame drops in Metro, but it just sucks you out of the game.
While playing Destiny 2 and Hitman on a laptop running Ubuntu and over wifi with a controller, it felt ok-ish. Almost on par with playing on a Xbox Series X but not quite there.
However, when I tried the same games on my gaming rig, on a 1 Gbit fiber connection with a mouse and keyboard it was completely unplayable for me. The input lag is just too high for me to enjoy the experience. On top of that the picture quality is pretty bad compared to running the same game on your own machine at 4K.
My conclusion is that Stadia will not replace a high end gaming rig for the type of gamer with higher demands. I even doubt it will replace xbox or playstation for the console players.
That's pretty low bar to clear