Can an expansion survive without a DPS?

[Absurdity]

We will eventually get to the point where it is no longer feasible to add new jobs due to job dilution and the limited resources of the dev team.
How soon that will be, we do not know but I would guess that its probably sometime around 8.0 or 9.0.

We've already passed that point long ago, their job design team hasn't increased in years and having only 4 people for 19, soon 21 (22 including Blue Mage), jobs is already showing it's problems, and has been for arguably two expansions.

It is not feasible for so few people to create satisfying designs for all of these jobs, so you end up with a bunch of "palette swaps", a whole lot of different flashy sparkles and no substance.