Harry Pearson claimed to have coined the term "high end" in audio back in the day; I don’t know if that’s true, but to trace what is considered "high end" I think you have to look at the history of audio reproduction devices. First, those of us in the States were not necessarily clued into what the Japanese or French were doing and were largely limited to the audio press in the US circa the ’70s- Stereophile, TAS, Audio and a few other journals, including J. Peter Moncrieff’s newsletter and a few other resources. The Internet did not exist at this time for normals.
In that era, which I lived through, it was probably easier to distinguish: it was not a receiver, plastic-y turntable and a set of bookshelf speakers (although some acquitted themselves well). Instead, it was separates- preamp/basic amp, table with the ability to mount a separate arm (not an essential defining characteristic but still) and some form of speaker system that purported to do something beyond the norm: Stats plus woofers and super tweets, the Infinity series, various combinations (that included using Maggie bass panels), bi or tri-amping with active crossovers, the use of more rarified cartridges, etc.
There were also DIY’ers that I knew back in this era who cobbled together pretty good systems based on older components from the "golden age," including tubed Marantz, McI, Rek-o-Kut, Bozak, KLH 9 (double sets), ad nauseam.
Integrated amps were not part of this, though today, with the lines to differentiate equipment blurred by low cost equipment, that is no longer true. The "quest" was to spare no effort, which often, but not always, meant expense, to achieve something that represented the cutting edge of home music reproduction.
We have become inured to unrestrained hype, expense and hyperbolic reviews to the point where it is difficult to separate the true, enduring milestone components from the chaff. I don’t pretend to have superior knowledge, I just lived it since around 1970 and built systems for myself that represented the best that I could accomplish-- I went from a mini-HQD system running ARC tubes and an SP-10 in the ’70s-early 80’s to horns and Lamm SETs with a substantial vinyl front end in the early aughts. I spent more than the average citizen and have a very good system but I don’t claim to have an ultimate system, only one that works for me. (In fact, I have a vintage system that represents a good approximation of what I was running in 1975 and it is very enjoyable, also all tube, Quad Loudspeaker and the same SP-10 I had in 1973).
Today, the lines are blurred. You can buy separates at low cost, and high quality integrated amps that didn’t exist back in the day. Speakers run the gamut- there is no "one way" and a lot, as all of you know, is getting the system to work in the room, not just hardware. Plus, we have credible digital sources today which did not exist for consumers back in the early days of the "high end."
I do agree that it is more a state of intention than one of price, although given the cost of gear today, a lot of the top tier stuff costs. I’m glad I got into this 50 plus years ago, and while not complacent, I’m no longer on the "quest."
I’d be hard-pressed to give you a better perspective; much is context.