In my experience the quality of a game suffers a lot if it is f2p. The last f2p game I played was Star Trek Online and what eventually drove me away was that Ithey were actually making annoying (and grindy) content on purpose so that players would rather pay for a shortcut rather than play the game. Pay to NOT play? That's insane.

A sub based game can focus on making a good game with good regular updates. When players are happy they stay. Win-win.