I think all of us to an extent, but YouTube talking heads more than most, conflate density with build quality. To me, well built means that something achieves its purpose as efficiently as possible and will continue to perform as long as possible without repair. I don't think anyone can decide how well built a camera is by picking it up at a camera show. Some have said the Z7 doesn't feel as well built (or well made) as other cameras. How can that possibly be determined. Did the body flex under load? Did something fail to work? Did it need repair already?
What we all do associate with quality (perhaps subconsciously) is density. So while we pine for lighter kit, we often perceive less dense objects as less well made. For example, the Zeiss Loxia 35mm f/2 weighs about 340g. The Nikkor Z 35mm/f1.8 weighs 370g, but is almost exactly twice the volume (178 cm^3 vs 360 cm^3) so it is going to feel very different. But it appears it will significantly outperform the Loxia and has AF to boot. I wouldn't want the Nikkor Z to weigh 680g (Sigma would). But this lower density can only be achieved using different materials whose densities we are accustomed to associating with more failure prone objects. But these materials are often stronger and less prone to shock damage than traditional metal construction.
Only time will tell how well built the Nikkor Z system bodies and lenses are. But thankfully aircraft engineers, bicycle riders and glider pilots know that well built and dense aren't the same things.
Excited to hear more about Bernard's experiences with his new camera!
Glenn