If you can believe Boeing, they listened to mechanics quite attentively.
I have a copy of the April 9, 1994 supplement to the Seattle Post Intelligencer that is devoted to the 777. Page 5 is entitled "Collaboration Delivers the Goods" which describes the input the designers received from mechanics. Here are a couple of excerpts.....
"But Boeing's chief mechanic (Jack Hessburg) acknowledges the company's new teamwork approach to building airplanes is light-years ahead of past business practices."
"Airline mechanics, who were rarely consulted by Boeing in the past, now attend weekly brainstorming sessions to discuss strategies, critique the airplane's systems, and even help write the airplane's maintenance manuals."
"In God we trust, everyone else bring data"