Steam can just bar you from playing those games though if they so choose. The only thing preventing that is Gabe. But that guy will have to retire some day.

You do not own shit on Steam.

I know what you mean, but you still don't own the game, you have permission to play it, at least as long as the platform lets you or it closes. For now it's all good, but when the time comes people will loose accounts worth thousands of bucks.

Who has to pay a monthly subscription to play a game? When? How?