LOL - I'm actually a guitarist. But I can only agree with your curmudgeon theory to a point. I have four kids and can tell you they consume music and video very differently. Yea, they think my home theater and guitars are super cool but beyond being impressed for a moment, they go right back to listening to their Airpods and watching Tiktoks on their phones. An upgrade to them might be a BT speaker. Maybe. They consume everything in bytes (pun intended). There is a generational shift in how media is consumed and there is nothing "curmudgeony" about it - its a fact.
And I'm not a guitarist?
Of course, media is nearly a 100% different thing from when I was a kid. As a child all the way through HS, probably college too, I had no interest in anything my parents had for more than a couple of minutes. Let alone a HT. But I do see most the young kids (starting out after college) have big screen TVs, soundbars, and a streamers. So, generalizing that kids don't give a .... is being a curmudgeon! So I looked up some stats and found:
Under 30 vs 50+ years old (I randomly chose these ages)
- Owning a TV: 81% vs 84%
- Watching TV: 2 vs 3-4 hours/day.
- Viewing media on a phone: 4-9 vs 2-3 hours/day
Owning a TV is pretty darn close. The TV watching is about what I was expecting. The stats say TV watching goes up with age too. Which may still turn out to be true. Overall viewing combined is clearly ahead for under 30yo's. I can't help but think as they age, TV watching, no matter what they're viewing, will go up and time on their phone will go down. Especially if technology makes it seamless. As I've aged my eyes can't stare at a smart phone screen for as long as they used to. There's clearly be a market for TVs and HTs. HTs has always been a niche market, and it may even be argued with soundbars it's more popular than ever.
What TLS Guy proposed, and I agree, is making a HT system with basically as many powered BT (or any other wireless standard) speakers as you want. Or even a single BT amp going to passive speakers. It's simpler and an extension of modern technology. The latter being the most important part for the end user.