Steam has begun making clear that you're buying a license to play a game, as opposed to actually owning the game.

There comes a point in most experienced Steam shoppers' lives where they wonder what would happen if their account was canceled or stolen, or perhaps they just stopped breathing. It's scary to think about how many games in your backlog will never get played;

Steam is now showing a new disclosure on its store checkout screen that clarifies you don’t actually own a game.