If FFXIV did rehauls of jobs as radical as you claim WoW has and does regularly, I think much of the playerbase would bail, or we'd see a similar "vanilla or not" phenomenon as WoW has. Even with the level cap increases and role pool consolidation, jobs haven't changed on a deep, fundamental level.

This is an appealing feature of FFXIV since we don't need to constantly learn a new job unless we choose to. If we leave the game for some reason, we can just pick it back up no problem. This is by design.

It's called accessibility.