From a business standpoint... you don't want someone to come in, get to cap, and play ALL of the content within 30 days....
your subs will definitely suffer if that is the case

People only want to beat everything... and many wont even care about farming all the gear if it isn't necessary to beat everything (Which is how it is shaping up)

So SE either needs enough content to keep people playing OR a longer leveling process at 2.0
Remember... many players in this game will be less likely to farm the same content over and over to get the rare drops because they'll be able to beat EVERYTHING without using those drops and uber gear
If 1.21 was 2.0.... players would get to 50, beat Short order Ifrit ONCE.... Short order moogle ONCE... Speed run AC/CC Once each and then stop playing.... we are obviously die hard fans and such... but for most people... what is the motivation for getting a Darklight set? to help you beat content that you were already able to do just fine without it?

2.0 will have admittedly more content... but the same logic applies