Everything is supply and demand.
Potions and flasks are burned every single day of the week, in Mythic plus, along with raids. Maybe even in PvP, the stuff is being shuffled out of the economy at a rapid clip, which keeps up prices, despite multiboxxers keeping prices low enough that normal players still don’t make much off it.
The problem with the other professions is that demand is very very minimal, and they’ve lowered the barrier to entry for people wanting to get into crafting. In the old days, MOST people didn’t get into crafting, because it meant going from 1 to 600+ before they could make anything worthwhile, which kept supply low, which meshed okay with the low demand.
With legion and BFA, they removed barriers to entry, so if timmy wants to be an inscriptionist, it’s 30 minutes of time spent to be an inscriptionist. That means supply is almost infinite, but the demand for most inscription items is VERY low, which makes the professions almost worthless. The same is true for all of the other non-consumable professions.
I’d argue that they need to double down on ‘progression’ for crafting. It should be a month long effort, maybe even more to max out a given profession, that would address the supply issues that are going on with professions in general.
Second, they need to start adding either meaningful consumables to each professions, OR make crafting a legitimate source of endgame gear that can be SOLD. The legion BOE legendaries were a good template/start to that idea, the notion that a crafter can make a single really nice item on a cooldown.
If a crafter could spend weeks making a maxed out BOE, you’d see enormous value return to leatherworking/jewelcrafting/blacksmithing/tailoring. It would need to be an involved process, with some sort of cooldown gate to make sure it didn’t create excess supply, but would go a long way to making crafting in general ‘better’.
My fan fiction would be a complete overhaul of crafting into something closer to FF14’s system. Same with gathering. I’d give almost anything to convince WoW dev’s to actually make gathering/crafting it’s own engaging game.