In the distant past I never questioned whether High End equals High Fidelity. And then it has happened to me (in 2002) that I heard a guitar recording (made with my guitar) that my musician friend made (without processing or editing, straight recording, only level was adjusted). I have listened to him play the guitar between my speakers and the recording to compare one right after the other.
I think very few have the chance for such hard core comparison for fidelity, with an instrument I intimately know, and my musician friend, whose playing I have enjoyed for uncounted hours in my lifetime. Plus, unadultered recording that allows looking into fidelity.
Through my system at that time I had no trouble identifying the exact guitar on the recording - after two notes I knew on which guitar he picked for the recording. (He has about a dozen guitars, all with different tones.) My system gave about 90% of the detail level of the actual guitar being played. The tonality was right, the perspective was right, the image projected was same size as the real guitar. The recording proved to be high fidelity, giving me 90% of the original sound. Now, this was through a heavily modded Dynaco stereo 70 - Fostex Voigt pipes - heavily hot-rodded purist all-silver PAS3 preamp - heavily modded Micromega Stage 3 CD player system - al DIY cabling including PCs (all DIY, yours truly).
The "High End" comparison was BAT and Wilson speakers, and I forgot which very high end CD player & transport & MIT cabling - it was SOTA at that time, and the league of the most expensive High End one could put together in that year. What I heard was very striking, and also a tremendous blow to the head forcing a MAJOR reality check and reorientation of my goals. Yes, there was a jump in detail level, but it did not sound anymore like listening to my guitar from the listeners position. It sounded as if I stuck my head within one foot of the guitar (yes, I have done such experimentation with real guitars). The tonal balance was totally askew, and I did not recognize my guitar anymore. If I was asked to tell which of his guitars he played the recording, I could not have guessed it because it sounded like none of his guitars. And the closest pick would have been a guitar that had a distinctly different tone.
So, while it was evident to all that the HE system in question provided a much higher resolution / detail level, it was also obvious that it completely failed at delivering both the tonality and the perspective / spatial balance, and in general, the EXPERIENCE of the recorded actual guitar.
This experience taught me that High End does not necessarily equals High Fidelity.
Since then, I've been investigating what is the difference between "High End" approach and "High Fidelity" which we could call "Reality" or "Real World Audio" (hence my moniker.... LOL.)
The key components necessary to provide High Fidelity AND high detail level: no feedback, efficient loudspeakers, as short signal path as possible. The more we deviate from this path, the easier it gets to get ultra-detail&freq range &SPL but at the price of the tonal balance.
To me, tonal balance is essential, and in my experience is the singular parameter that makes or breaks High End to behave as a show host or the translator of reality.