One can think of it by analogy to STEM subjects.
Lots of people love jet planes and robots and rockets and fancy chemical reactions.
Lots fewer people love figuring out why their computational fluid dynamics simulation doesn’t converge, how to program a visual learning system to tell a ripe apple from an unripe one, how thick the combustion chamber wall needs to be, or fucking titration.
Similarly, there’s probably lots of people who love the idea of magic and even the practical parts of it, but writing essays about the uses of dragon blood, not so much.
That’s something that struck me as well when I read it. “Wow, D’artagnan’s…pretty sure he’d be prosecuted for rape nowadays. Don’t see that in the Mickey Mouse version.”
Like, Dumas’ prose is still wonderful, but I definitely have to put a lot of product of its time filter on when reading.