From a design standpoint it makes no sense and cdpr simply double their workflow for no reason. There are, I belive, 4 body types on npc's if V shared those body types problem solved. But, now we have the issue of clothing. I'm sure you all have noticed the npc's dress better and have better options showing that yet again cdpr double their workflow for no reason by creating a separate, and imho, vastly superior wardrobe selection for the npc's.
A way they could fix this, but likely won't, is allow V to share the npc's body morphs, unlock all npc clothing which would be body style locked as most of it appears to be in game, then morph/adjust all of V' current clothing for the 4 body types. Most of V's clothing variety is just different textures so no need to redo any of the maps unless they have to break the uv's when morphing the clothing.
Essentially it becomes a wear what you see deal and Bethesda has been doing this for years so no clue why other developers don't take note. Fact is, sadly, I think no matter what they add to the game Cyberpunk 2077 is always going to be an 'NPC'S look better and dress better than you' game.