For example, I’m sure the average joe doesn’t know just how expensive calligraphy pens can be, or how deep the rabbit hole goes on video game speedruns.
Don’t forget commander, which a lot of places claim is now the most popular format. Pre-constructed commander decks can cost as little as $20-40 and competitive commander decks can easily go into the thousands.
The game also has a very high skill ceiling. I think that’s one of the main reasons why magic has such a broad age range to its player base. There’s plenty of weird lines of play, from strange card / rule interactions to weird deck themes no one else would think of.