On the other hand, its an inefficient allocation of resources for infrequent gamers (who might play games 100 hours a year or less) to need to own expensive consoles or PCs to play games.

I hope Stadia or a similar service succeeds, because I'm one of those people.

You can just sign up for Geforce NOW beta, it's free for now, you automatically get all the games you have on Steam, it works and it probably won't go away anytime soon.

I doubt Stadia will replace computers for people who take gaming more seriously than the average gamer. It's a large market segment that isn't going away.

Anecdotally, as someone who games regularly, I never even looked at the Stadia. It was of 0 interest to me. I suspect most people in my position feel the same.