"Crafter specialization" is not some kind of a magic wand to fix the economy, either for specific items or in general. We had that in FF11. Being able to make a decent profit on an item only lasted so long before a ton of other people decided to also make that item and flood the market. The only way to keep any particular craftable items at a good profit margin is to have a wide variance of highly desirable craftable items that consistently sell. If, for example, the only things people generally wanted were class weapons for relics, eventually the price is going to completely tank, regardless of how many hoops you have to jump through in order to craft them.
At a certain point, it starts feeling pointless to continue mining for low HQ rate, crafting materials with good HQ rate, crafting with mix ins from vendor for low HQ rate, crafting parts with mediocre HQ rate, and rarely if ever HQing the end product... Some people will keep trudging along flooding the market for less profit than before while others get disheartened from their terrible luck busting 2-3 darksteel ingots and/or 5-6 flawless parts in a row and consider the whole thing a huge waste of time. Even when folks bow out, that won't help the prices, because those who remain will continue to make huge volumes of the item.
Granted, it's still better than FF11, where you couldn't sell anything of value at anything but a HUGE LOSS unless it was HQ, where you often barely broke even, considering how many other people made the same item and apparently didn't do it for the gil. It ended up that most of anything worth selling (for a high price tag) was drops, not crafted items.
There's definitely stuff that could be done to improve the economy, but crafter specialization isn't one of those things. After their last great effort on this, the super terrible materia system (which is the most luck-based nonsense in a game that is mostly luck-based), I'm really not interested in seeing them try to fix it anymore. Granted, it did "breathe life" into the economy, but I don't think we're better off for it, unless you're really lucky and super love to kill mobs in SB gear all day and night.