I don't know if it's just me but lately I happen to come across a lot of those “hear popstar in her isolated vocal track” click bait type of “news”(!)
I think it’s not fair to the musicians and performers to expect a record like quality in their live tracks, especially if they put on a show that requires energy, you know, jumping dancing running around and all that.
Sometimes foldback monitors may not work properly; a bad job at mixing, acoustics of the venue may prevent artists to hear themselves as they should. Zillion obstacles like that may prevent even an experienced artist to perform poorly from time to time.
Moreover, an isolated track would never truly represent the overall sound of a band as an ensemble. For example, you might take, say, a guitar track #5 of a legendary album and it may sound weak, ahead of the beat, behind the beat, etc. But it would have a purpose in the recording, it would add muscle, spice to the lead track.
Often times, a little imperfection makes wonders, creates unforeseeable richness in a tune. Whereas if you were to listen to each one of those tracks by themselves they wouldn’t be all that impressive. This is especially true in albums that were cut live, where 5-6 musicians may not necessarily on their best day and be playing perfectly but yet if they catch the right groove together, that is more special than playing “perfectly” individually and yet sound like nothing but a boring clock.
I think musicians would know what I’m talking about.
Anyway, take care.