I spoke with a Boeing aerodynamics engineer in 2000 or so... When I told him then I was impressed with some of the airbus treats that we lowly wrench turners appreciated... things like easy access... His response was as genuine as it was perplexing...: "I don't think we've ever spoken to the guys who fix them for their input." Whether true or not at the time, I do believe they Have done so since... the 777 is a fabulous plane to work on/fly in/play with!
Recall that during 777 design, Boeing hooted loudly about the wonders of the new CAD/CAM system they were using to design it. Adverts showed little computer-generated people proving easy access to internals. I wonder if they still use it.