Some consumers can be fickle like that.
Most people seem fine with that, and Steam totally killed the physical games segment. There's GOG if you want a copy without DRM, but they're tiny and the prices are often worse than Steam or a Steam reseller.
Besides, if the game rental model is bad, Stadia does it even worse than Steam: tiny library, horrible pricing, incompatible multiplayer, proprietary ports on a different update schedule, exclusivity deals, all from a company with a proven history of abandoning their customers.
Steam on the other hand is run by one of the oldest, most respected PC gaming companies in the history of the hobby, owned and run by a bunch of gamers (not advertising execs), who singlehandedly transformed the way people buy and get games, and worked tremendously hard to make the service better abs better every year in the service of players. They've earned our loyalty.
And furthermore, Nvidia is the provider of GeForce Now, not Steam directly. Their model is just way better, running off existing Steam and Epic games that don't require a new port or for customers to repurchase or lose their save games. Nvidia is also a gaming company. Not exactly as beloved as Valve is, but at least they're a long term player in the field.
Google just never really got it, at all. They arrogantly assumed they could just make a mediocre copycat and people would flock to it. Oh well.
VS the days/weeks/months it took you to port to Stadia, only to have the entire service shut down.
The point is that there are many PC streaming services that are basically "no porting required", whereas Stadia opted for a strange sort-of-console, sort-of-not model (despite PSNow and XCloud already being able to stream actual console games already) that required you to spend dev hours porting your game.
It backfired because most devs didn't want to (or couldn't afford to) port their x86 game targeting Windows to some tiny proprietary platform, ESPECIALLY when it's Google hosting it. Of the few that did (Orcs Must Die), Google arranged some exclusivity deal with them, lying that Stadia could do things no gaming PC or cloud streaming service could do due to Stadia's special scale or something. It was a lie. When the exclusivity expired, it showed up on Steam and GeForce Now and ran perfectly fine, and got a lot more players to boot.
Stadia had some really awesome tech -- namely the UX of being able to boot straight into a game without waiting for Steam Big Picture -- and some nifty (but relatively useless) side features like being able to capture a memory snapshot and resume that later, emulator-style. But I don't think their management really understood the PC gaming culture and what was truly important to its user base, and failed to take years of pleading and feedback into consideration. They just arrogantly did... something else (or nothing much? I can't really tell)... with Stadia and drove it into the ground. So sorry for all the engineers who worked on it and had to see it nosedive like that due to managerial incompetence.
None of this was a surprise to any gamer actually watching this space. Stadia came late, delivered less, and exited early. Google's product culture doomed it from the get-go.