I think it was actually a definite answer, just spruced up enough to hide the downside as best they could.
They did say that you would be able to use Google Takeout to get your data (saved games) in the case that Stadia folds - which leads me to believe they've thought about this enough to know that users certainly won't get a copy of the game.
While the saved game is nice, since you won't lose your progress (I still mourn the death of my 400+ hour save file for Disgaea on DS - I re-bought the game with no regrets, but those 400-some hours died with the old cartridge), it's a tough sell when you have to basically say that the safety net is that you can still go buy the game elsewhere and have your progress.
I won't judge people for jumping in to Stadia, because it may fit the needs of other people more than me, but I'm 100% not going to be an early adopter. Likely not at all.