There is a possibility of survival, Bobby at Getchell Amplifier W of Indianapolis seems to be making a living at it, as does Brian at Misfitz Audio in Grand Rapids, MI (no affiliation with either other than as a customer).
I see a lot of mid-line silver-face stuff in Billy's store, reminds me of a store in the Detroit area that has sky-high prices on everything, store is packed, and nothing really high-end to sell.
I love stores like Misfitz where they tend to keep some really nice stuff around, even better at a store like The Audio Solution in Indianapolis is a dealer for some high-end brands, but you'll have to walk through mazes of used equipment in each room ranging from a Transcriptor TT on a landing half-way up the stairs, huge used tube amps, servers, last time I was there an SX-1980 was still sitting on a counter (trade-in) that was there in my visit weeks before, ... not even on the short list for restoration.
My suspicion is that there are plenty of these stores around the country, some do well and some don't. Misfitz started when Brian realized that he was storing garages full of vintage audio and it might be time to do something with it, I know that Bobby Getchell also has at least one storage unit I've been in besides all of his back room stock but started out building guitar amps. The Audio Solution has been a dealer who takes trade-ins of all kinds (including a really cool big-block Chevelle that has since sold) and ends up with lots of cool used stuff.
I do think that having a really good tech is important to make it work.
