You're banking on their goodwill here, not any actual obligation they might have.
> Even with physical games if you let the device connect it can be changed or prevented from working entirely. I get that you _want_ this but considering you already don't have it, I don't understand why this would be taken out only on Stadia.
Is this so? There's a huge aftermarket of games for a reason. People buy old consoles, from NES to XBox 360s, all the time. A lot of people prefer physical media for this reason too.
Even for heavily DRM-d content, it's just a matter of technical skill and people with the will to crack a game to catch up to the techniques used to keep it locked. With streaming there wouldn't be anything to crack. You simply don't have the game, period.