It's an unsustainable model that gives short term benefits, but is going to look really stupid in the long term.

Say someone comes into the game with the PS4 version. What incentive will they have to run ANYTHING other than what they're forced to run via story mode? Once they've hit 50, finished storyline, the only thing new players will do is run the dungeons that drop the highest item level gear.

CT can be bypassed, along with WP and AK. Why? Because you can go into Turns 1-4 and die until you get the echo buff strong enough to farm the place. Instant item level 90.

The current model is pushing out content every three months, true. But, that content is then almost completely invalidated with the next patch.

Or, say you're a player that has everything at 50, has run through all of the content and decided to take a break from the game for a while.
Say you come back into the game after 2 patches.
What will you do?
You'll check out what content drops the highest item level available.
You'll do any pre-requisites to get access to that content.
You'll do solely that content until you get the highest item level gear for your job(s).

There will be TONS of content that you just won't do. Why? Because it's invalidated. There's no reason to do it.