Teemu
Hero
Another common argument is something that popped up in this thread as well, which is something along the lines of, "I'm a master of my craft, a powerful wizard, yet this apprentice mage has a magical ability that I can't learn. This doesn't make sense and takes me out of the fantasy." This line of argument seems more prevalent to me and this is how it's usually presented. An NPC spellcaster stat block features a custom ability, and it feels off that a powerful PC of the same class couldn't ever learn or acquire said power. Yet that's going to happen even with full PC-NPC equivalency.There are some combinations of abilities (often, many combinations!) which can't be learned concurrently, yes. That's not what the claim is saying though. The claim is saying that any individual ability should, in some way, at least conceivably be learnable in the abstract. An individual ability that cannot ever be learned under any circumstances is a violation of this principle. Concatenating even two abilities together does not strictly guarantee that you should be able to do that, but any singular ability, in isolation, should be accessible to the player via some means; and if the ability is from official content, then an official means must exist to reach it (even if that means is "well you should have been playing an actual literal dragon if you wanted that, even though actual literal dragons officially aren't an option for player charactesr"), even if doing so would exclude literally everything else. Some means of acquisition for each individual ability should exist, even if no means exists for any given collection with more than one element.
Anyway this is probably splitting hairs. I see the argument for learning NPC abilities coming from the POV I laid out. (And I don't think that it's a sound argument in any version of 5e.)