In Google Stadia, game plays you.
If they are going to predict your inputs, what happens when it gets predictions wrong? You’d have to train some machine learning algorithm to figure out how good you were at the game, so that it hit the right buttons the right proportion of the time, and the game would basically be playing itself whenever your input agreed with what the algo thought you’d put in. But when your input disagrees with the algo, what happens? Do you start to do the right thing, then cancel the action and do the “wrong” thing? Does the stream hitch up a little bit and not feed you those frames?
It would be funny if the algo realizes that you’re just terrible, and it can’t predict what you’re going to do, so the game feels extra laggy for you.