I have a stadia and use it daily, I mostly play assassin's creed odyssey, and some thumper, and other trying to shoot with a bow where aim is important, I don't see any issues with it at the moment.
It's a fairly good experience, but the thing that sells it for me is the fact that I can easily move around the house and play, be it chilling on the sofa after a long day of working on the pc, or picking it up on the pc when I feel like playing there.
They certainly have things to improve, like the lack of vp9 working out of the box on Chrome browser, giving a much worse experience on pc vs Chromecast, not to mention a bunch of other minor things. But for me at least, the service itself works just great.
Also, I don't live in a major city, I live in a small village in Norway at the far end of a fjord with about 30/10 internet +-5.
And considering that Microsoft is working on their xcloud, doesn't Nvidia also have something and Sony?
I can see why people wouldn't like the service, but I don't think its going anywhere