It makes more sense as time goes on, as publishers limit micro-transactions for the press reviews, and even provide a much simpler overall grind to increase the fun factor, initially. Then when a game comes out, the micro-transactions go in full force, resulting in either hundreds of hours of grind, or just spend $30 here and $25 there.. The glowing reviews are already out, even though the core gameplay design changed.
F2P models are very different. The free players populate the world, making it more enjoyable for those willing to spend money to do so, without fear that their game is dying, or will die... because it's free .. and free games are generally populated for long stretches of time, which spurs even more spending.
F2P also includes occasional free content updates, not paid for DLC.
P2P, B2P, and F2P all seem to attract different types of people, although with some overlap. From past experience with AION, I believe people playing are more open to spending money to support their game, even beyond $60 with F2P games.
Other category players seem to feel jaded at spending more, since they already paid for the promised experience, leading to the sensation of feeling "cheated". They can't simply walk away, as could be done in a F2P title, since they already committed themselves by purchasing the game.