With 12 classes it would take an age to cap out every class though. Ignoring gear sharing (it's been a long day at work) and assuming 6000 tomes per class, you need 72,000 to buy everything for every class. That's 1,800 Fractals (without roulette bonus), or around 650 hours of play time.

I don't see caps as beneficial once content has been cleared, they only frustrate and limit players (for instance those who level late or gear job A but switch to job B). From my perspective time caps just turn the players against the content as they're punished in game for not doing something (behind the curve with no way to catch up), rather than rewarded for doing it.