This is actually such an important statement. Ultimately, every patch has a finite amount of resources that can be used to add content to the game, and it's the producer's (Yoshi-P's) job to allocate those resources in the most effective manner possible. In order to maintain the rhythm of content that we have released in each patch, it's become quite clear that the bulk of resources that are allocated to job design happen at the start of an expansion. The patches in-between are far more limited in the kinds of things they can do. Adding something like Monk's new masterful blitz, for example, was something they couldn't afford the engineering of mid-expansion, which is why all they did partway through Shadowbringers was sterilize Monk.
Thus it's far more important to ensure that each job has an engaging playstyle before going into an expansion even if it's poorly balanced because changing values like potencies, MP costs, recast times, etc. are much easier to do and can do a lot of good work at restoring balance. We also don't have much raiding right at the start of an expansion anyway, and they can do some number balancing by the time Savage comes out to calm the balance mob.
And honestly, I think we are too demanding of balance as a community anyway. I think each job should have something of value to offer, but FFXIV has almost always had enough of a balance between each job that none were deemed "unplayable," and the few times we did have an emergency situation, it was pretty swiftly rectified anyway. Sure WHM was still the worst healer in ShB, but its MP economy gave it something it could better than the other healers, and while not a major benefit, it does add a layer of ease to prog and general healing that can be appealing. Thus we didn't really see much of the healer balance mob across 5.X (most of us had our pitchforks sharpened for other reasons).