I wouldn’t be as categorical as you are. Some live performances are worthwhile some not. Especially some old ones where there was energy, yes, but very often, a poor sound (due to technology available).
Im into prog rock, and I like the sound perfection of the true studio album. I’m sorry I prefer studio album from dream theatre - can’t stand Labrie live, even Portnoy, live, annoys me. I love Floyd, but Pulse... I can live without.
On the contrary, Porcupine is as tremendous live as in studio, Marillion is often too mellow in studio (bad mix) and much better live. Anathema wasn’t that good live, but Universal (live) is so perfect. Iron Maiden, I like the energy live, but prefer their studio sound.
Some live performance can be messy (Metallica anyone?)