A lot of comments in this thread demonstrate that gamers are just scared of change.
Never change a working system, as they say in IT departments
Personally, there are 4 things that I'm afraid of with streaming:
1. History. What happens to an MMO of it gets shut down? Nowadays that data is saved and conserved at some players. But that would be impossible to do if it only gets streamed, very possibly loosing a part a videogame history forever that way.
2. Modding: For similar reasons, mods are not possible. Pretty much disqualifies a lot of strategy games with this btw.
3. Pricing: You say there's no big investment in hardware needed, which is true... but I don't think you'd get a Netflix style streaming platform for peanuts. Unless you play a very lot and otherwise have to buy tons of games, the console pays for itself as it's cheaper over time.
4. Infrastructure: For the advertised 4K60, better have some 50Mbit connection without any hiccups or data caps (see below). To which only a minority even have real access to. Due to the amounts of data getting used by this, expect digging up roads to lay more and more cables to cover demand.
Well, even worse then. With 4K being 4 times more information then Full HD, then 100Mbps is probably necessary. Very very few have even access to such speeds. The 1080p60 is already out of reach for quite a lot of people with this.
I'll use this post to talk about what i've thought about overnight.
Streaming is the future but _not_ the whole future. There will still be physical games. There will still be Steam, there will still be consoles/PCs, there will still be games that have modding. Fallout 76 (whatever you think about that hot mess at release) has mods, even if they are quite limited. Plenty of MMOs have modding.
Think of it like this. A game like Skyrim, since its already pretty much on everything, including refrigerators. Plenty of people play that game vanilla only. So those people might go the streaming route. Others like me will play on PC, modding the shit out of it.
Pricing will of course be all over the place. Stadia i'm sure will eventually have multiple pricing models to compete will SONY, MS, Nintendo, Steam, etc.
And yeah, this is going to be a slow roll out. At best I don't think this will see its final form for 5 to 10 years. The infrastructure is really not there for 4k60 for way too many people, although I have to say frankly I won't be moving to 4K anything for quite some time. I am not replacing any of my TVs for at least 5 years. The required 25Mbps for 1080p/60fps is obtainable for more people than we think. Those that want it in the more populated areas will be able to get it. Again, this is not going to explode into success, it will have to slowly grow.
Stadia is only one part of a growing need for more internet infrastructure. 5 years ago I could _only_ get 40Mbps. Now I can get double that if I want to pay the price. I know many people hate the fact that the internet keeps getting more expensive for the same speeds, but that is just where we currently are these days with these companies and politicians. Who's to say that won't change.