I don’t think the cap is the contributing factor in keeping people subbed - I think it’s more likely that housing, crafting, rp and other activities do, so increasing it sightly I don’t think would kill the game. And because of these other activities, SE really doesn’t have to do anything.

If you’re a battle focused player, you can get full tome gear in 8 weeks?, quit the game and come back a year later and it would still be there,