Well, build quality doesn't actually demand a premium, but what you are talking about is material quality, not build quality but that still doesn't have to demand a premium. Aluminium and glass isn't actually particularly expensive, and funnily enough often has the opposite result in what people want. They say they want premium, that they want their stuff to feel "quality" yet when they drop it, it hits the ground harder and breaks because of the added weight, yet they still fall for the "premium materials" thing.
Note that I wasn't talking about professional reviews, I'm talking about when people feel the need to justify their purchase by saying things like "but build quality(material quality really)" as a justification for why they've spent so much.
Personally I'd have more respect for such people if they just said "I didn't care about the price, I wanted so I bought" or even better, not feeling the need to justify it at all.