Earlier quoted context omitted.
I (and many, many others) notice lag in games with v-sync turned on vs off, and we're talking about single digit milliseconds there. It's possible that Stadia might be "good enough" for casual gaming (and granted, that's a very large market segment), but I don't think it will ever be good enough for anyone who is sensitive to latency.
This is something which irks me. All major engines (Unity, Unreal and even Godot) provide 2 different mechanisms for callbacks in your scripts: A callback before each rendered frame and a callback before each physic step (Update() and FixedUpdate() in Unity). Now, physics always run in a fixed time step. Usually 60 times per second. If you move your player, the game will always need to wait for the next physic callba…
E.g. Dota 2 and CSGO servers in Europe have <40ms ping for most people. Local lag should be up to some 16ms from a 60Hz display plus 1ms from a 1000Hz mouse/keyboard, half of that on average. If the hardware is bad, it could easily be some extra 30ms from the display and maybe 16ms from the mouse/keyboard -- think 125Hz poll rate and bad debounce implementation.