Why pay so much?

"...high end audio would be available to the $50,000 a year salesman who works 50+ hours a week, and who would love to listen to all the notes of the music, the "way music is supposed to be heard" in terms of notes, etc."

That would depend on his other expenses and disposable income, not on his absolute income.

At the same time, there are many audio reproduction items in the lower price ranges and they still sound great. Most of them are.

$70 000 speaker cables are rare as are $250 000 speakers. Quite good under-$1000 amplifiers exist together with decent $1500 speakers. I have no idea if that particular salesman would find them "too expensive" or "just right".

"If people wouldn’t pay it, they’d drop to 500%."

Every time I tried not to pay for something they did not lower the price. They simply did not give me what I wanted.

Sub speakers that are $1,000 should cost like $250-300 and get 1,000%+ margins.
The same goes for other "cheaper" alternatives of processors and amplifiers.
If a Dayton Audio (Parts Express brand) had their affordable $30-50 drivers used in speakers from a 300% margin speaker company, it’d rock the socks off anything over $1,500 that exists at like $300-$350 for a 3 way speaker. Again, speaking in bulk 50% wholesale large mass driver and crossover components and building materials.
You can get 5 channel car audio amplifiers that puts out like 1,000 watts RMS for $200 on wholesale sights.
I don’t see why they can’t have $300-400 versions of these on the home theater market.

"...and I’m assuming the speaker industry threatened them in to not doing it..."

They got "backlash" from it, and wow...

Remember, it was just your assumption, not the known fact, but you built your case on it.

Apparently the D3004-6600 was, too "neutral" and not "lively" enough, but good enough for the Anat Reference II at $100,000 which won awards for the best speaker ever at the time.