Why can't spells be sold back to the vendor?

Some also buy spells/songs/tomes for their next level(s) if they're going to be going out to a remote spot and/or are close to a ding.

I think any spell that is sold by a vendor should be made lore because there is no reason to really need more than 1 of them. All the rank 2 / 3 spells could be left as not lore since depending on the expansion alot of them are only drops and aren't like the modern expansions where it is a token and you can't use it to get 2 of the same spells.

If they want to require you to go buy from some special vendor that is fine still leave them lore and no drop so you can't buy 1 and take it to another toon but it also stops you from buying more than 1 and forgetting to scribe it and not being able to sell it back.

/output missingspells