I'm not convinced that the best high-end from now is necessarily better than the stuff back then - different perhaps.
Okay well then you could stand to get out more.
Starting from 1973, all the way on through to today, I've been comparing and buying and upgrading. Your doubt is probably only justified because you haven't heard as much stuff as I have. Its absolutely not true. Some of the best bargains in history are being made right now, today. And yeah they come dear. Nothing new there. Always have.
Now full disclosure, what I am going to say is far from true for every manufacturer. Plenty make overpriced doo-dads. I'm only talking about the best. More to the point I'll talk about the one I have 30 years direct experience with: Synergistic Research.
Two concrete examples. My speaker cables and main interconnect were SR Resolution Reference level from the 90's. They cost roughly let's just call it $1k each since I've long since forgotten. Well, ask yourself, what could you buy back in 1993 for $1k? So not only the components but the money itself has changed. But that's another subject.
Anyway back when they were made I was hooked up real good in the audio biz with access to home audition pretty much everything, and with a dealer trusted enough if he said there is nothing better then guess what, there really is nothing better. Or at least every time I thought he'd be proven wrong he wasn't. So I had a pretty good knowledge of the market, and you totally could not do better than these, certainly not for anywhere near the price.
But the trick is when the next generation comes out and you go to upgrade. Which I have done across two generations: Resolution Reference (non-active) to CTS Active Shielding, and Resolution Reference to today's Atmosphere Level III Euphoria. The RR speaker cables went from about $1k to $7500 for CTS. I got mine used for $1200 and had Michael Spallone mod the MPCs, but even before that they were a huge, and I mean unbelievably huge, step up from RR. Same story with the interconnects, except the latest generation Atmosphere no longer requires active shielding and is another huge leap up in performance.
Actually just got off the phone with Betty at high end-electronics.com who will be sending me some Orange Fuses to upgrade my Blues. Prime example for you, as everyone says the Orange is improved more relative to Blue than Blue was to Black. For like $10 more you get like $150 worth of improvement.
These are by the way for $150 more improvement than most $500 power cords, not to mention something not even available 30 years ago. So you totally get what you pay for. You just have to make sure and find the ones worth it, and not just go blow it on the first thing some web boob blabs on about.
Is there any logical explanation for this?
Of course there is! Everything costs more today. That's one. So even as as fast as productivity increases money depreciates even faster. (See: fractional reserve, fiat currency.) But then also some of this stuff is just plain harder to do. Ted Denney has to buy a freaking Tesla generator that sounds like a hurricane just to quantum tunnel a fuse. Maybe you have priced Tesla generators, I haven't, but I bet they don't come cheap. Then too you got precision skilled assembly. Most of all over everything you got the cost of building and testing tons of failures and dead-ends. A task that only gets harder as we get into the thin air of perfect.