Is remote rendering a thing? I would have imagined the lag would make something like that impractical.

The lag is high. Google was doing this with stadia. A huge amount of money comes from online multiplayer games and almost all of them require minimal latency to play well. So I doubt EA, Microsoft, Activision is going to effectively kill those cash cows.

Game streaming works well for puzzle, story-esque games where latency isn't an issue.

Hinging your impression of the domain on what Google (notoriously not really a player in the gaming world) tried and failed will not exactly give you the most accurate picture. You might as well hinge your impression of how successful a game engine can be on Amazon's attempts at it.

GeForce NOW and Xbox Cloud are much more sensible projects to look at/evaluate than Stadia.

It doesn't matter who does it. To stream you need to send the player input across the net, process, render and then send that back to the client. There is no way to eliminate that input lag.

Any game that is requires high APM (Action Per Minute) will be horrible to play via streaming.

I feel as if I shouldn't really need to explain this on this site, because it should be blindingly obvious that this will always be an issue with any streamed games for the same reason you have a several seconds lag between what happening on a live sports event and what you see on the screen.

GeForce NOW is supposedly decent for a lot of games (depending on connection and distance to server), although if Nvidia totally left gaming they'd probably drop the service too.

It will be if personal computing becomes unaffordable. The lag is simply mitigated by having PoP everywhere.