First sale doctrine gives you some rights, but it doesn’t give the all same rights you would have for any other physical object that doesn’t include copyrighted work.

If I buy 100 chairs, I’m free to start a chair rental business. If I buy 100 copies of a game, I cannot start renting them out without permission from the actual owner of the game.

The fact that the law entitles you to a slightly broader license doesn’t take away from the fact that it’s still just a license and not ownership. The only thing you own is the physical media (e.g. the plastic disc) not the contents of that disc.