The fact is high end dealers do not really compete with direct sale companies, it's a totally different market. People who will go buy from dealers generally won't cross-shop the direct sale alternatives. Direct sale goods are limited in price to speakers around $10k, components under $5k and cables under $1500ish. Above that the folks who will go to the effort to maximize their value through buying from direct-sale companies can't afford it.
The fact dealers have gone out of business in the mid market isn't due to direct sales either, it's due to economic conditions... especially after the 2008 depression. The US and some other countries have horrible economic issues, wages have not kept up with the cost of living and the middle class is now not so middle class and the lower class is now living in poverty. But the folks making above a certain amount of money were more or less insulated and now have too much money.
When Henry Ford began production of his cars he had to pay his workers more than was customary at the time so his employees could afford to buy the cars, paraphrasing, he said something like "It's better to have 200 people that can afford to buy a car than one person who can afford to buy 200 cars." Nobody needs 200 cars and the money just sits there doing nothing, helping nobody. Money just sitting there is worthless, and because of interest our economic system encourages it. So about 64 people own half the world's wealth, and you can bet it mostly just sits there, a complete waste. Edit: Well, actually their money is used to buy politicians who will look after their own best interests.