I've worked with some talented designers in the past, and this rings true every time. They are often seen as great designers because they don't compromise, and the result of that is a happy designer, a not-so-happy client, and an unhappy development team. It's been almost shocking at times how little some of them have known about basic web standards, and how leading design teams have been built by people that would consider things like mobile-first to be "a fad".