Studio albums are toyed about with and rehearsed several times, until you get "perfection" in the eyes of the mixer and the artist.
Live is different, it's a one-shot, everything from the FOH technicians to the communication between band members and the supply technicians is there, meaning that it might not be as "tip-top" as you want it off a sound recording through a piece of equipment for that, but depending on who's on the mechanics, who's playing (as in, how talented is the band) and how well they know each other, you can have a really awesome gig (let's face it, anyone who intends to put volumes as high as you would at a gig will either be deaf because of the room size, would be stopped by the police or wouldnt have the equipment to even touch gig quality talking in studio).
Just your local ignorant teenager's opinion.