Steam very specifically states that you buy a license for the game. Unless someone somehow takes over the license agreements with publishers, your game library disappears.
GOG very plainly states your ability to download game installers to have as a backup to prevent this ever being an issue. They could go under and say “you have 3 days to download your games before servers go offline” and you could.
Bioshock, the first one at the end. “Would you kindly”. I lost my mind.