There has been a lot of debate about this, especially after the CD became prominent in the mid to late 1980s...... The audio science types were promoting CD playback fervently during that time, claiming that LP playback didn't extend much above 15 kHz...... (I think they're probably correct, but I do notice "sparkle" at the top end with a good analog source that I've never heard with any digital format, regardless of resolution.)
Prior to the CD era, it was believed by many that high-frequency extension beyond 20 kHz had a profound effect on "spatial cues"..... The one thing that I remember prior to the CD era was that "soundstage" extending beyond the speakers (and beyond the walls of the listening room) was a common phenomenon with systems that were capable of extended response.... In spite of the systems being quite modest by today's audiophile standards...... (Although I sometimes wonder if I had better hearing during that time, which may have contributed to the effect.) And many of us believed that to maximize this effect, extending well beyond 20 kHz (as far as going up to and beyond 50 kHz) was a key factor in attaining this sonic quality.
But after the CD came out, the obsession with "huge soundstage" faded, quite dramatically...... (I also believe the proliferation of digital devices and computers, due to the increase of ambient RFI of several orders of magnitude, has made it very difficult to restore this sonic trait, even with systems that once excelled with it prior to the digital age.) And even with high-resolution digital audio playback and vinyl exotica, this obsession has never been rekindled.
