Masoner,
there are quite a handful of F2P MMOs that run on a "premium item/subscription" model that are actually successful. Warframe, MechWarrior Online, War Thunder, Cabal, Entropia Universe, Exteel, Gunz: The Duel, MapleStory, Ragnarok, Runescape, the list goes on. Some of the ones I listed have been out for over 3 years (Warframe, MWO, and War Thunder being the most recently made games). However, the majority on that list have been around for quite a while, and have always offered the open of F2P or premium accounts/items (meaning you aren't forced to pay to play).
Not all F2P's are failures. They are only failures if they lack the proper marketing strategy to get money from the players.