I don't care what class my amp is. I have an Asgard 3. Apparently it's Class A/B. I don't know what that means. It's like a modified class A. It gets very hot but so what? I don't care. It's a headphone amp - it's not going to be using that much power. Class D all seem very expensive and large. Why? Are they over complicated? Are they ever going to become less complicated? Do they sound better? I thought the Asgard 3 measured amazingly well - as do all manner of other very inexpensive headphone amps. So what does class D solve? Why would I - or this new idealised hypothetical teen we're all staking the future of hifi on - be interested in it?
OK, your point deserves something other than flippancy. So does
But I don't know how much, if any, effect it might have on Gen X or millenials. Probably not much. I don't know of any who sit home and listen to music. Video games and streaming TV are more their thing.
The future of audio is contained in these two comments, I suspect. We are seeing the death of the conventional stereo system with a big amp and two loudspeakers - in this particular place, we are concerned with science that tells us of the probability that people prefer surround systems in controlled testing, home theatre is the point where that is happening - the big end of streaming video now - and audio VR via headphones is to my mind a coming thing, because who needs 360 degree immersive video without matching sound? Even soundbars will continue to evolve and improve, if you buy the good stuff.
There are hints that people are moving away from streaming TV now, driven away by each big new thing being on yet another paid service and a likely reduction in quality of shows as the market fragments. I see music coming back into the mass market more, but in a different form to what we oldies are used to. It will have to evolve to play on home audio and immersive systems used primarily for gaming. Among the younger "classical" musicians I'm acquainted with around here, in fact, music written for games is having the kind of influence that movie soundtracks have had over the last few years for music listeners more widely.
For the next decades, I see music as existing more as part of wider experience, rather than just on its own terms, and audio innovation will not be a new form of an existing technology but new forms to match those wider experiences. We may have fewer musicians in a broader sense but those attracted will fit in happily and profitably. Pure music will continue to exist and its time will come again in some way. It always does. Music is too interesting to the brain to just go away...
That's not new. It existed in mass market TV in the past - we've had threads about theme songs here - movies, musicals and opera before that. And there's always been dance, of course.