I used to work for a west coast tech giant. The UI designers always laid screens out on paper (literally paper printouts with a crude mockup of a mobile phone on it) and reacted with outright personal hostility to my suggestion that their designs be tried out on focus groups before being put into production. "Users don't know what they want" was something I heard many times. The UX people always supported them, while doing - so far as I could tell - nothing whatsoever themselves.
Our apps got tons of one-star reviews, usually with comments like "I gave this app one star because you can't give an app zero stars".