MMOs require a certain amount of subscriptions to be on the green light. The cost monthly fee goes into paying the bills of server, customer support, a team dedicated on making sure the game is running well, a team that is dedicated to producing new content, payment to investors (although FFXIV and WoW investors are the parent company), advertisement, and so on.
All MMOs require a way to make income in a monthly basis. Even Guild Wars 2, a game who's main attraction was the no monthly fee has a cash shop. F2P survive by bringing in new people that are lured into it by the fact you don't have to pay monthly and then using psychology to nickle and dime them. Some people are adamant about refusing to buy anything, and that is fine, but for every few people that is not buying anything, there has to be another person buying x2-10 times more than a P2P game would normally charge you.
I can give you an example because I have done that. I have an account on Perfect World Internation. I started playing that game because is free to play. My inventory was small, I bough a super inventory stone. My bank was small, I bough a bank extension item. Over 2 years I nickle and dime things that I felt I needed. By then I had a nice group of friends in the game and I felt weak so I bough Rank 9 armor. Keep in mind, NO ONE MADE ME BUY IT. By the end of it I was playing a game with little updates, outdated graphics, and crappy story and had spent $2,000. I had fun, but when I think about it. I could of played FFXI, a much superior game for 10 years and still not spent that much. Is my fault for spending it and that is fine, I can live with it. I'm just telling you that no one goes into a F2P thinking they going to spend a dime. It just happens, and btw; my Rank 9 gear is not even the best anymore, Stage 3 is out and refines to +12 makes my armor look like nothing. There are people who spent way more than I did, you can tell the cash shop buyers by their ability to 1 hit kill you.
I'm not saying F2P model is bad, but is definitely not in the best interest of consumer. They give you limitations to TRY to manipulate you into buying things without ever saying so. Because money is sporadic (they make huge profit a month then little profit the next one), content is always lacking. They may have an update every so often but most update you will see will be cash shop items being introduced. There is a heavier emphasis on making money creating items than actual game content.
In a P2P model, you know you pay such and such every month. The developers focus on providing the best experience profit because that's how they make their money. They don't have to think up of new way to nickle and dime, they can focus on the stuff that actually matter. Everyone paying a similar fee, everyone starts the same. You can't just buy your way to being the best, everyone is in the same playing field. My personal favorite is that most people who are playing a P2P are there to stay. Of course people quit, but having played F2P (PWI, Tera), I can tell you people quit a lot faster or are constantly talking about a different F2P they look forward too. I kept hearing about Blade & Soul, Scarlet Blood, Rift, and ESO on Tera all the time in area chats.
I really do understand that people don't want to pay to play. For those people, I recommend they play Tera, Rift. or Guild Wars 2 as they to me the current best B/F2P games. Some people like to eat at fast food, but I prefer a buffet.