Maybe I don't want to have to read Learn You a Haskell to configure my window manager. Maybe I hate the whole concept of tiling window managers because I like to have overlapping windows?
You are making a lot of assumptions about what other people should want to spend their time on. I don't want to waste time or brainpower coding xmonad or dwm to behave in a way that doesn't annoy me, and manually setting up a bunch of basic infra like automounting USB keys, when I can just use KDE which doesn't annoy me by default.