Hi End Audio's days are no more "numbered" now than they have ever been. This is a niche segment of the market. It's always been so, and always will be.
I'm not sure what people think the market for high quality audio is, overall, but my guess is they vastly over-estimate it. Yet, the products are out there, and we can buy them. I think that is a great thing, and a testament to how seriously the players in the industry approach it.
They are not getting rich off it; if that were the goal, they would be selling some injection-moulded lump of plastic with one 30-pin connector on one end and a 2.5mm phone jack on the other, with some wire in between, and packaging that probably exceeds the manufacturing cost, to the masses, so their iPhone does some thing or another with some audio product.
Many people remember the "scandal' of the oppo blu-ray player and the Lexicon clone of it. I won't go into the details, or comment on how fairly or unfairly Lexicon was seen in the whole affair, but one thing stood out in the information and statements made by the players in the drama.
Lexicon expected to sell thirty five of these Blu-Ray players, worldwide, through their dealer network, during the product's entire retail lifespan. Yes, I said thirty five. This was the projection at the design and development stage, not some reflection of the reduced sales potential after the mess they got into once both players hit the market.
A Hi End manufacturer who sells 200 copies of a product is bordering on the mainstream, sales wise. Some are more successful, but not everyone can be a Bryston or a Rega. The industry is composed of players who can hardly be accused of market ambition. They can be accused of innovative ambition, and that's why they are in the business.
So, I have no idea how you would measure success, let alone determine whether it's days are numbered. There has to be a baseline somewhere to judge improvement or regression; I don't think that baseline would be believed, even if you could get a company who wants to cultivate a reputation for success to tell you exactly how many products sold that their idea of success represents. They'd be afraid to, frankly, because the number would impress no-one.
I had a buddy who built really, really nice motorcycles. 3 a year was his measure of success. He made most of the parts individually, from billets of metal. This was a time when a very expensive custom bike would not get a $20,000 sale price; he was selling his for about 12K. I remember talking to him in his machine shop ... do the economics on that little investment, if you're so inclined ... and the subject of people who didn't want to make improvements, just ride a stock example, and take it to the dealer for service, and maybe let it fall apart a little bit in the meantime. Treat it like a truck they might have in the garage, instead of a special machine.
He said "Well, they just don't give a F*** about bikes."
He didn't say it in a way that was derogatory, or dismissive. It was just reality as he saw it every day.
So, maybe ask yourself the question. And as long as some people answer "I do" the industry will be fine. Because it's not an everyman industry in the first place.
Even if the market for Hi End was 1 in 1000, and I don't believe it is or ever was, that person isn't going to buy one of everything available. He's going to buy one of a thousand offerings, once, and probably keep it for a while. So, right away, we're at one in a million for your sales target, assuming your product is at least competitive. Lord Help You if you're in the speaker business, where 1 in a thousand doesn't come close to the product choices available.
There are players in this industry that would be happy with selling a dozen copies of their audio product in all of Canada. They're still in business. I know of products from the late 70's ... a boom time for audio ... that never sold that many copies in Canada. They were pretty happy with the sales results.
I'm not sure what the price of the equipment has to do with the success or doom of the industry. The wealthy, in my experience, are less interested in Hi End than the average Joe is. The prices just reflect the cost of selling a low volume product into the market. More people into Hi End might lower the costs on average, but it's never been a cheap hobby. And although costs are a concern and a barrier to entry, they don't stop people from entering the hobby. Not caring about audio stops people from entering the hobby.