Seeing as I am much too lazy to read 20+ articles on the subject, I'll just stick to my own opinion on the matter. F2P games, if they are games that are designed to only force a person to buy something from a sort of cash shop in order to complete a portion of the game, are pretty rip-off ideas that only those who really do not have any better time on their hands would do. The "demo" format is just as bad, if not worse (runescape being the biggest example here) than that of the pay to win format. For a demo format, A player would have to play the game for a certain period of time before realizing that he/she cannot move much forward unless the necessarily BUY the game in question. Then, they get many new benefits and rewards and other crap and rise to be much greater in the game because they decided to make that upgrade to continue growing in the game. The only good f2p format I can really think of is when there are cash shops, but only for vanity and little trinkets that really don't add too much help in the game to the player. The only game that I played that did this though, was mabinogi, and mabinogi's community is dead at this point in time. Ironically though, f2ps tend to bring and attract the worst type of communities though, because when you aren't paying for a service to play on, then you really aren't serious to take as much time of it seriously as possible. You might just blow off a week to act stupid in a f2p format, while in a p2p format, you'd want to play as much as possible before the next paydate.
to be honest, I think it's pretty stupid to even waste any sort of cash on f2p games, but when you have the money, you're willing to waste it
it really is scary to think about though.
EDIT: and another thing, what truly defines a MMO game is its COMMUNITY and the people who make the game. The game can be all awesome in gameplay and whatnot but once you get used to the gameplay then you only go towards the community to help you stay even slightly active in the game.