I can't say how much is much, but in my view, looks have far too much to do with the general public's perception of audio gear. This is a nice way of saying it's looks first, and the rest comes "naturally".
As a very common and basic example, take the insanely thich aluminium front plates. These days, they go as far as a full inch - and more! - thick. Yet, to this day, I have never once heard any technical or acoustic justification for this aluminium reselling. A couple of times, vibration control was hinted at; while I agree greater mass tends to resonate less than low mass, I can think up quite a number of methods of dealing with the very real vibration problem far more effectively for less money. And if we were to ask some of the real hotshots working on that problem for such not completely unknown organizations like NASA, I'm sure they could write volumes on the topic.
Yet, if you don't use a thick front plate, and massive volume knobs (again, good up to a point), you have nothing, nobody is interested, nobody takes you seriously. The fact that you gear plays better music than the other, thick plate stuff, seems completely irrelevant. And it's not just front plates - these days, if it ain't got a computer inside, well sheesh, it cain't be any good, can it?
About the only bastion of sanity left I can readily think of in terms of groups of audio users, beside isolated individuals, are the DIY guys. They sure care about the insides a hell of a lot more than about the looks. Maybe it's because they are an integral part of the manufacturing process, in which they too have their say, while classic passive buyers are reduced to only plonking down the money.
But that's the way it was ordained to be when audio became such a big business; for lack of ideas, true, advance design, manufacturers resort to visual tricks.
Cheers,
DVV