I don't agree. If the NPC is basically a PC not being played by a player, then they should conform to the same rules as the PCs. Let's say you're playing an evoker wizard, and your PC meets some classmates from the Evokers Academy. I would expect those NPC evoker wizards to work the same way as your PC. Sure, one or two of them might have learned something that your PC didn't learn, but they should still operate using the same underlying structure (leveled spells and spell slots).
Instead, going by the way WotC has done it, your PC is the only evoker wizard from the Evokers Academy who didn't learn the Arcane Burst cantrip. Even the piddly NPC apprentice wizards just starting out at Evokers Academy know that one!