Between rewind scratches being already released and remaking old items for NGS this is as close to confirmed as "probably never going to happen" as possible.
Ignoring that, though, the gacha is a necessary evil in order to allow F2P players to obtain cosmetics. If people could buy whatever they wanted directly, then
- Only popular items would get bought
- Very very little would get put onto the market
It would be better to sell cosmetics as packs (like the nier collab) rather than individually because of this.
Also, if they did do a individual cosmetic purchase catalog, the prices for everything would be much higher than 100-200 AC. Scratch draws are 200 AC (500 for CAST rewinds) because you are expected to have to pull several times before getting anything you want (guaranteed pick at 3000 AC (6000 for CAST)).
though i must say there are a few cosmetics i'd gladly drop 30-60 dollars for if i was given the option