1: Aaaaaaand? A subscription is, yes... quite alike a cellphone contract. but it is the most stable Pay model for a online game possible.
2: The wow shop... (even if I dislike it quite heavily) is litterally as far from P2W as possible.
All the mounts and pets are cosmetic (except pet-battles, but honestly, nobody plays wow for PvP pet battles), the helmets (the three of them) are some of the most disliked transmog pieces in the game and don't even have stats, ONLY costmetic. and the 100 boost? THAT isn't P2W. It is P2C (Pay for convenience)
It is for those people that want to try a new class at max level (or level an alt to max level) but don't have the time that they are willing to spare on it, so they pay to get a character up high so they can do the interesting stuff. You won't win any PvP or PvE content easier because you do it, it is just for those willing to spend more money then time.
3: Wrooooooong, people constantly earn money to buy PLEX. Sadly have EVE (after about 12 years I think) implemented a "free" model. Where you are a alpha clone, but can't get the skills to fly the big ships and stuff... so you are basicly a grunt. But EVE didn't truly fail because of its model, but rather because of its difficulty curve and generally "grindy" gaming style. IT is REALLLY hard to start up in EVE, unless you find a good, newbie friendly CORP...
4: STO (Star Trek Online) is garbage. I am sorry, but as a new player trying it, it is pure shit. The graphics are ugly, the game is slow and clunky and much more.
Also, do you know WHY F2P models even works? It is based on a single concept in the game industry, WHALES.
WHales is what you call players who spend ENORMOUS amounts of money in the game, I am speaking tripple zeroes worth. Basicly THEY are the players that keep the game going, making sure you guys can play for free. Without them, POOF... a game goes up in smoke cause it don't earn enough money.
MMO's are SUUUUUPER expencive. They are the most expencive game type in the gaming industry, "F2P" isn't TRULY F2P... more like "Letting Someone Else Pay 2 Play" so "LSEP2P"
5: F2P models are the LEAST worthwhile paying way of them all. It brings in a UNSURE amount of money and it is never 100% sure if they will get what they need each month, the reason it is "vastly more popular" now.. is because companies understand 1 thing.
People won't pay a subscription model, for a game they don't think is worth it. WoW, in all its glory, is the best MMORPG on the market (in pure content and player base) and when people start playing another MMORPG (that is like wow) they automatilcy think,
"huh, this game is great and all, but I could be playing WoW instead". IF the game isn't free, they have no reason to pay money to play that game, since they can play wow instead... BUT if it is free, then they can play the game on the side when they want, since it don't cost them money. You get the point?
The ONLY reason that wow has gotten as big as it has, is because of its subscription model, it has allowed it to gain a steady and safe income, with a clear way to plan and check their income (basicly they can look at their subscriber ammount and say ROUGHLY how much they will get by the next month) WHICH allows them to plan and produce content according to that.
They can take it slow, focusing on quality over quantity. Making grand things, while F2P games have to CONSTANTLY pump out loads of content and updates to keep the small, uninvested fanbase interested, so they don't leave for another F2P game. You follow me here?
THERE. You have gotten answers to everything.
DU is going to be SUB, and due to it honestly being unlike any other MMO out there at the moment, it could REALLY succeed.