DT - As are, I believe, many of the folks who frequent ASR and do so with an eye or ear of skepticism.
I got interested in audio as a kid in college in the late seventies, when a thousand dollars barely bought a decent quality system with, speakers and cassette deck (and turntable) and an amp/ receiver over 25 watts. And in those days, $1000 was big money when the minimum wage was $2.35 an hour.
Today, with a cell phone, a DAC (dongle), a Class D amp (hopefully with a power supply ) and a pair of good desktop speakers like the Elacs, etc, a college kid in 2020 can own a system for three hundred 2020 dollars that would give my 1978 system a serious run for the money.
Ain’t technology great?
To answer your question more directly, with quality speakers attached, I’m zeroing in on the conclusion that spending over $750 to $1000 gets you a system that, to my diminishing level of hearing, quickly becomes more about looks and how it makes you feel than the quality of the sound you hear.
As for connects and cables, I think that point is reached somewhere around $10 as fellow ASR cynics will frequently point out!
To wit, per my earlier posts in this thread, the fact that I just picked up an AO7 to play with goes to this point: For $65, today, I can buy a Class D, throw away amp that will sound almost as good as the Harmon Kardon Citation amp and separate pre amp that took a big chunk of my summer savings in 1978 just puts a stupid grin on my face. (And to be able to roll op amps with this AO7 - which I’ve never tried before - is all the better. Frankly, I’m surprised there isnt a separate thread on op amps for the 07 or mods for the case for fans, drilling the case etc. to better cool this little amp like we see on single board computer forums like the Raspberry Pi.)
My $ 0.02.
Cheers