What the large print giveth, the small print may not taketh away. If the large print says "Buy", the small print may not alter that to "License for a limited time that may be ended whenever we feel like it." The small print may clarify what the large print says, but direct contradiction is a form of false advertising.
I just now checked Ubisoft's website and clicked on a random game. Yes, there is a big "BUY" button, but once I click it, I get a page that asks me what length of time I want to purchase a subscription for. So it's quite clear, at least for that one game, that what you are buying is a subscription to something, not a product that you get ownership of indefinitely.
The game sellers, if someone did actually try to make the "false advertising" argument, would probably argue that it's common knowledge that "buying" a game from their online store does not mean you get indefinite ownership. It would be an interesting case if anyone ever did try it.
