I’m not sure how Google will do their streaming, however streaming games is already something you can do. Linus Tech Tips did a video on Shadowbox (ignore click-baity title):
Shadowbox isn’t limited to a console, and can literally play pc games on iphones and androids. I think the only advantage of google’s console, from what I understand, is linking it with youtube/‘google’s data center’. Maybe they’re going to push for games as a service, I don’t know.
So I think that Shadowbox beat them to the punch in terms of the streamable games, the linus tech tips video came out 3 months before this announcement.