I guess I should have added "no longer works on mobile". PCs/Consoles have plenty of good, paid-upfront games.
If you're looking for a game to play on your commute it's probably not going to work, but for at home on the couch it's great.
But I guess they're harder to find/more rare. As others mentioned, most people spend nothing to little on these "free" games, so as a no-spend gamer you can choose between 1) free, or 2) pay $10 (or whatever they charge) to play a game. Not necessarily a hard choice if the "free" game is "entertaining enough".