Microsoft isn't buying up all these companies for fun. They are doing it to make their game streaming service the best. They lost the console wars but have a huge lead on the game streaming wars.
Agreed on the point you made that it's too early to tell. Lots of people are really certain on it being too early to tell. In my opinion, I think the issue with Game Streaming is one of input latency. Game streaming is already really cool and useful if you've used Steam's Remote Play and Remote Play together. Additionally, there was also Nvidia's Geforce now which I gave a try like 2 years back, but the games I played were FPS games and had too much input latency to be worth playing.
The technical problem is input latency, and the benefits aren't exclusive to games, but also to remote control of anything(Drones, rockets, etc). For streaming movies, it was a question of buffering all the data and compressing it down, and you had a predictable consistent video. Video Games and unpredictable inconsistent video, the same for audio and the same for inputs. This issue is worsened if you play multiplayer games too, as you are extending the input latency for you, adding network latency to the data center's server, and adding network latency to the game servers.
Some people would say input latency isn't very important, but something to consider is that a lot of apple devices are sold on this promise of low input latency, as android(thanks Chinesium software) and Microsoft(with their old line of phones, idk if they still do any(as another point, this is another thing about Microsoft. They buy the advantage and majorly drop the ball all the time)) have comparable worse input latency despite being more featureful. You also see this in how people who go 30fps -> 60fps -> 120fps -> 144fps etc struggle to go back as it feels choppier to them. It's also more points of failure, but that's the same argument for DVD vs Netflix.
That said, there is a massive class of Gamers who aren't very picky in their games. To the point some game developers hunt these whales in the google play store... and with how money talks...