I'd guess that's because fluent English speakers (especially those who write for a living) don't like to confine themselves to using basic vocabulary.
New words, one handy idiom, and a 2-minute quiz — delivered to your inbox to keep your streak alive.
Anonymous that premier novel in English, Moby D!ckI thought you would chose James Joyce's Finnegan's Wake as the paragon of all difficult text. I find this quote by Melville, a prescient description of Joyce himself: