I love me some FFXIV. There are a LOT of Jobs these days, so I can imagine it's difficult to keep up with the ever-increasing demand for story content there.
But... well, I kind of think that's a huge part of the appeal of Jobs.
I was honestly pretty shocked when Shadowbringers didn't have any real Job quests, but you at least got a little epilogue. For Endwalker though, there's absolutely nothing.
It's not so much that "oh, the game is completely unplayable now". That would obviously be ridiculous. However, I WOULD say that it kind of contributes to a general feeling us "well, I guess the game is pretty much over now, roll credits". Which obviously ISN'T the case, but it kind of FEELS that way, to me anyways.
Moreover, those Job-specific storylines are what really help you CONNECT with your Job. I think that's part of the reason (among many others) that people seem to be gravitating more and more towards "the meta", because when you aren't getting that story-based RPG content for your favorite Job, you're ultimately left with little more than "a bunch of numbers". And you can ALWAYS compare numbers, and factor which job has higher numbers, and is therefore "better".
Now, I honestly don't need to learn a new ability every 2-3 levels trough a quest. It makes for a nice carrot-on-a-stick, but it's really not THAT important.
However, since Endwalker has introduced us to the idea of ARMOR that scales with your level, why not make THOSE your rewards?
Let's say you went back and added Job-quests to Shadowbringers. Maybe at level 72, you get your boots, which will level with you and scale to 80. Every two levels, you get a small progression, netting you legs, gloves, chest, and finally helm. Maybe the lvl 80 quest nets you the helm *and* weapon?
Same thing for Endwalker. Every two levels, you get boots, legs, gloves, chest, and maybe helm and weapon at 90.
I think that is FAR more exciting than simply "talking to a vendor" to acquire those.
But even if you don't offer ANY rewards at all, I still think that STORYTELLING content is really, really important. It's what makes you really feel connected to your favorite Job.
Because without that Story content, you're really just hitting a series of buttons without any greater meaning.