You say "obvious exception" but.... I'm not the one who said they don't exist in D&D. Hells, they're literally in Wild Beyond the Witchlight. You can't say something doesn't exist and then shrug it off when you're proven wrong. And that wasn't even the ONLY way for that kind of thing to show up in D&D. It was simply the first and most obvious.
Legendary figures have an immediate effect on their "Lairs" - this can include people, not just liches and dragons and whatever. If you need a "reason" then they're a wild magic sorcerer who, by definition, doesn't have full control over their magic. Another possibility is that the people in question live in those verges, or whatever the supernatural landscapes detailed in Tashas are called. I mean, its not like we really have an explanation for how Lairs come to be, but we just know that they do.
Artificers aren't barred from using emotions as catalysts in their Imbuements or crafting. Or a bard-tailor, if you're inclined that way*. Farmers can have access to druidic magic, or just the favor of the elemental spirits who power druidic magic, and giant plants are just a minor blessing of minor land gods.
There's sooooo many "exceptions" that, frankly, its only DM fiat that NPCs can't improve or level that prevents all kinds of things from happening. Which is valid, but far from universal, so you can't even say this stuff is an exception. Just equally valid takes on the fantasy genre.
* Interestingly, I see a lot of tailors who rely on a variation of bardcraft to do their magics in stories than something more akin to wizardry, alchemists or mystic blacksmiths. Just a curious observation.