I agree with you. It's not a supply/demand thing in the sense of undifferentiated "widgets".
It's that the market mix has changed to the point where people who used to buy "stereos" don't buy them any more, they buy soundbars. And they stream music that is "lo fi" compared to higher quality sources, so they don't even use music sources that have high enough bitrate to matter.
So... The people who really care about it are now niche buyers, with exacting needs and perhaps less price sensitivity than the average "I need a soundbar" guy. So supply shrinks to meet demand, and prices go up because it's servicing audiophiles. Instead of a bifurcated market. There was always a high-end that served audiophiles. But there was also a mid-range that bridged the gap between people who cared about quality and people who wanted a small and reasonable jump up from soundbar-level quality.
I think what you're saying is that the midrange got hollowed out, and because you're too elite for the low-end, now you've been pushed up into audiophile pricing. I get it 
Absolutely this, said much better than I managed. Maybe you should get an MBA...

All that said, I'm surprised there aren't good options for powering passive subs.
Have you considered going full component? Split the receiver and the amplifier functionality and make them discrete pieces instead?
Hmm, it's a thought.
I'm not sure there's even a solution out there that will do it, though. And if there is, I can only imagine it's going to be even more expensive. If A/V receiver amplifiers have trended toward audiophile status, then you don't even want to know what's happened to discrete amplifiers. Once the neckbearded vinyl-hoarding fiends showed up in that market, everything went crazy.
But I guess it's worth looking into. What I'm not sure of are two things:
1) Is there a discrete receiver that has the HDMI capability? Seems like this has traditionally been the standard domain of the integrated receiver/amp marketplace, and I don't know if anyone ever bothered to service it with discrete components?
I know there are discrete receivers designed to serve primarily audiophile requirements, sych devices have existed for at least 70 years and still continue to do so. But I don't know if these ever really extended into the A/V market.
2) Are there discrete amplifiers that are designed to drive 5.1 functionality, with or without a passive sub? For the most part, the discrete amps I've seen lately are all stereo 2-channel drivers designed to service the HiFi vinyl neckbeards.
The truth is I need very little functionality out of the receiver portion itself. I don't need AM/FM, I don't need phono inputs or tape inputs or any other stereo inputs. All I absolutely need is 1 HDMI input for the BluRay, and 1 HDMI-ARC port for A/V output to the TV and return audio from the TV. An extra HDMI for a gaming console or something might be nice, but not really necessary since the kids have an entire play room upstairs with a big TV and all of their gaming consoles hooked up to it.