Alright… so as a 13 year vet, let me give you some reasons.
Eve is a difficult game to get into, its hard as hell to get hooked for a lot of people. When eve hit the market, most mmo’s were themeparks/guided. In other words, they setup rides and you ran the rides to get the prize. Or you went on a very specific path to get to said rides. A lot of people, and i mean A LOT, don;t want to think for themselves in games. they want you do guide them to point a and lets them run it, then go to point b. They want everything in a nice line with arrows.
This is one reason why eve struggled and never reached WoW levels. Another thing, is in order to effectively play eve it takes time. you can jump into a fleet fight from day 1, but if you want to fly a titan, it takes years. No ammount of grinding made you get a titan any faster (back in the day) and being solo was a bit of a disadvantage.
This kept people away. The issue is, this also hurts eve’s playerbase. As eve tended to have a slightly older player base (early 20’s to mid 30’s when it started, then people who had retired on the other end) As players like me aged (i started eve at 23, i’m 36 now) and had families and carriers, the time they had to play eve grew less and less. Hell i am lucky to squeeze in 1 hour a night, when i was playing up wards of 10 hours a day when i started. This caused some people to leave as they shifted priority.
Another thing, the market changed. People want simpler, jump into the action and do crap, games. EVE is not that type of game. People also wanted free to play, eve just recently got some of that.
These are mainly why eve was never huge. ‘pve sucks’ is not actually a valid reason. Mostly that eve is hard, take a lot of time to master and even a lot of time to do anything, is what hurt it.
Sure you can log in and mine or run a mission now, but thats not eve’s appeal. Thous large fleet fights? they take hours of planing, prep and coordination. Even something that happens like b-r once it starts takes a while for other forces to get there butting in gear, and even then that took hours of prep so someone could just jump in and go pew pew.
Its both what makes eve awesome and what makes it suck. There ya go.