These are my thoughts as well. They had a strong presence at PAX West one year and never saw them again in terms of marketing. They have a lack luster collection of game titles compared to other PC gaming store platforms.
There are also alternative streaming services that are built around your existing library of games from Steam, EGS, etc instead of rebuying everything through their own store (e.g. Shadow). This is far less risky in that if this service dies, your game library is left untouched because it's not something you need to invest with this service.
All of that combined, I just feel far too skeptical about the fate of Stadia. It feels like a service that Google is willing to pull the plug on at any given moment with your money invested just gone.