Maxperson
Morkus from Orkus
You've got it backwards. 1e introduced NPCs as just PC classes controlled by the DM. They rolled stats like PCs, had classes like PCs, had magic items like PCs. Henchmen and hirelings were PC classes. And so on.This is going back to the 1E and 2E Style. An NPC just had whatever powers they needed for the adventure.
Very often very specialized powers and abilities unique to only them. It made ever NPC unique.
Very often with very crazy unbalanced powers and abilities too. And a big player complaint was that it was not fair that NPC got all sorts of "cool" things that PCs could never have,
3E introduced the idea that all NPCs must follow the same PC rules, in general. And got rid of "special crazy unbalanced powers and abilities". Anything a 3E NPC had, a PC could also have.
As an Old School Gamer, you should just embrace it and make up unique NPCs.
It was 3e that introduced the NPC classes that were different/worse than the PC classes.
Could the 1e/2e DM create some new class or NPC abilities that the PCs didn't have? Of course. So could the 3e, 4e and 5e DM.