Those who will scrimp, save, upgrade or build upon a system owned for years are probably shrinking. I’m not even sure it has to do strictly with economics, but also lifestyle and priorities.
Those of us who grew up with two channel audio only systems for focused listening are aging out.
Although some younger people may get into the hobby, the market is far different- it’s portability, access through the cloud or on multiple devices, ease of use and cheap. (Look at the antique furniture market- dead. People want new, clean, almost disposable furniture; sure there will be collectors, but they fit into that top tier niche).
Let’s not forget that even when we Boomers were coming of age, we weren’t buying Levinson, Infinity Servo-Statik, Tympanis or ARC unless we were in deep (not average) and/or until we got some money-- usually earning power didn’t begin until a little later in life. I had some serious gear at a young age, but I was a ’nut’ and had access b/c I worked in stores at the time. The average system then- a receiver, a pair of bookshelf speakers and a modest turntable-- was not high end. People did get together and listen in a home environment- but this home listening activity wasn’t limited to the high end. It is an activity -- the listening session- that is no longer common, except to hi-fi nuts.
I think a lot has to do with how people live today. Spend a grand on a phone or 3 grand on a laptop or more on a big TV, but two channel audio isn’t really a priority. I think high end has been dying for decades. Remember how all the dealers had to shift to big A/V systems in the ’90s to stay in business? That was twenty or more years ago. I think the hobby will survive. It already has. The names may change, but there will always be enthusiasts.