Have to put a lot of hours into it if you want to be good at it, gear wise. It's not a game you can play casually, so I wouldn't put it in the same category as AH where everyone is playing with the same "gear" and the only difference being skill level.
You're correct in the above, this game doesn't force you to grind for gear/planes, which puts it head and shoulders above WT for that alone, warts and all.
However, if you want to be decent at this game, most people have to put in the time to build the skills. Depending on peoples' capability and talents, this can either be easy, or extremely time consuming. And much like in WOW, many people are content to just play for fun, not try to be the bestest firstest, and play at their level of skill.
The commonality between this and games like WoW is they take some kind of commitment to be good at/succeed at. The number of people who are willing to commit significant time to a game is dwindling rapidly, as can be seen by the rise of casual gaming on the phone/tablet. The majority of people aren't willing to lay out money for a decent computer and all the gear for a game like this. I think that's the single biggest factor in why games like this are falling off.
*glances over at Star Citizen* Ok, yeah. I'll grant the point that's wildly popular, but it's also a huge, fondly remembered franchise and I think once it goes gold, there's going to be a metric buttload of disappointment and player dropoff in that game.
A phone/tablet F2P simplified GV game would likely be more widely popular than the current game, but it wouldn't be the same game. May as well compare Fallout 4 to original Doom. The broad strokes are the same, but the actual gameplay is vastly different. A lot of people who enjoy AH wouldn't want to play some arcadelike fighter plane shooter on a tablet, just for the controls alone.
A game like this and a casual tablet game just can't coexist in the same space. They could be two excellent separate games, but they won't mingle well, as can be seen by the wild number of complaints about certain control schems being superior in the games that try to split the difference like WT and Star Citizen.
Wiley.