9) There are plenty of reasons why a character may not drop the items they are wearing. I mean, if someone dies in combat there's a significant chance their equipment is damaged for one. Not to mention resizing equipment across different body types ect. With the variety of justifications you can use, for things like armour and clothing it really is a design choice about progression. Also I don't recall flaming fist in bg3 specifically wearing full plate. Maybe there were budget cuts in the last 100 years?
I do believe the DnD5e rules actually state that most equipment enemies are wrearing are considered to be damaged and of no value. (This to allow enemies to wear plate, while not giving it to the players).
This to me seems mostly for balance reasons. Heck it takes ages for players to even get Chain Mail, which is starting gear for many classes in 5e.
