Having experienced the difference between proper acoustics with really great gear then gear costing 10% in the same exact space and still having a great system I am a firm believer it is the most important aspect in audio.
In business I used to sell a dang fine automotive sound deadening product and did quite well at it, growing monthly for years in a row and without advertising. I hired a new web designer and he kept after me for months to significantly raise my prices though I had a really decent profit margin I felt it was wrong to do so. Of course it involved fancier packaging and a new name but I finally gave in and the business grew 4 fold in months. I never really liked doing so but I still had what I felt was the best product for the money available and more got to get in on it.
I came up with some ideas for a very dynamic website, had not seen some of those used before, spent a lot of money and a lot of time waiting for it. In the end the guy used my money and ideas to develop a competing product, quite good, tiny bits of product, very slick marketing and charged a huge price for it and sold a lot of it. In reality it was not better than what I sold, just marketing BS.
That said, I think there is more than enough evidence to support claims that gear is being sold that is way over priced and just does not perform that much better than other quality gear to justify the prices. Mainly it just sounds different in some cases and in others goes with the system better than other gear and or the way the customer perceives how it sounds can be related to our differences in taste and preference or just simply how our individual hearing works.
BUT, it does keep more money in circulation, not a bad thing for the rest of us that do not have the budget or do have the budget but choose to be happy with "lessor" systems.
Rick