We are talking about how NPC rules are written in general. Of course we are talking about multiple NPCs.
But that
literally was not the argument being made:
If an NPC Elf can do X-Y-Z-A in combination then a PC Elf should (and IMO must) have the potential to be or eventually become able to do X-Y-Z-A as well.
Flip side: if a PC Elf can do B-C-D-E then an NPC Elf should be able to do likewise.
This is not "every single NPC (of a certain type) uses X, therefore my character should be able to, too." This is "if
any NPC (of a certain type) uses X, then my character should be able to, too."
Your claim is a for-all type. His is a if-there-exists type. The two are completely different (indeed, literally reversed), and an argument against the latter will be completely irrelevant to an argument against the former.
I mean there is rather obvious middle ground where the NPCs are streamlined, but still use same spells, weapons etc than the PCs. Small disparities are not usually apparent. A bunch of NPCs repeatedly using a spell that is not a PC learnable spell is.
That is a contradiction in terms. That is like saying "Where you draw a square, but with only three right angles."
Anything in 5e that must "use the same spells, weapons etc." cannot be streamlined. Period. It's not possible, unless you restrict the spellcaster in
numerous ways. Weapons are probably not an issue because there's only like twenty of them and they functionally never change. Spells? There's
hundreds of them. Even if you restrict to a single class and level, there's usually dozens, and it grows with every new book.
Because if you're already using 1:1 matchups there....you are just creating a PC. Which means it cannot be any more streamlined than just creating a PC yourself.
That's the problem here. You want something to be streamlined, without allowing any changes to the parts that make things complicated!