Why does rock concert sound suck?

@barts + 1 - Yeah, I saw/heard that 'Wall of Sound' a couple of times, and Owsley was doing their sound from before that, almost as far back as their beginning. He was brilliant, and the Grateful Dead live sound quality continued on well past Owsley until the end. They always had serious sound systems and sound crews.  

I'm not a big fan of the audience singing every song either. The first time this really bothered me was at a Tim McGraw show about 15 years ago. I think every audience member sang every song, and very loudly too. Guess what, I didn't pay to hear the *audience* sing these songs, I paid to hear the *artist* sing these songs. If that's now the norm, see ya later. 

Happy I saw Pink Floyd throughout the years on two different outdoor stadium tours. Sound quality always seemed to be perfect. I know for sure that one of those tours supported a quad sound system, and it sounded excellent. I saw Christine McVie when she was touring for her 1984  solo album. It was at a venue that was noted for symphony performances, and not only was Christine's performance stunning, but the sound quality was outstanding. I'll never forget it.

I will also mention a few live recordings that I think incorporate the venue well - Chicago Live at Carnegie Hall, and Atlanta Rhythm Section's Are You Ready.   

@dpop Totally agree, drives me nuts!. Really crazy how audience behavior has changed over the decades. This as it pertained to rock concerts and personal experience. Early 70's audiences rather reverential in that they were totally engaged with performance, quiet and even sitting in their seats with exception of encores. This behavior was common at indoor venues, outdoor or festival audiences far more rowdy. Over time audience participation increased, I really think Peter Frampton's Come Alive release exacerbated the audience as participant in performance thing, Springsteen certainly added to it.

As far as recent sound quality at shows, I've seen Railroad Earth, Beach House and War On Drugs at same local venue, Railroad Earth best of three. This theatre has pretty bad room acoustics and house sound reinforcement guys have no idea, louder and louder better for them. Railroad Earth saved by being more acoustic based band. Saw Kraftwerk recently at another venue, much better room acoustics here and house sound reinforcement guys controlled volume much better.

The problem largely lies with house sound guys and equipment, you learn some venues never produce good sound. In order to get good sound, very high likelihood band has to have their own sound guys,  equipment, and how many bands have the resources or even care about good sound quality to do that.

After attending a couple of terrible sounding shows at an outdoor venue in San Antonio, I swore I'd never attend another show there. That is until Steely Dan was booked. I figured if their sound guy couldn't tame the sonic issues there, then no one could.

Sure enough, it only took him about 5 songs into the opening act (Michael McDonald) for Steely Dan's sound guy to dial in the sound. So, as has been mentioned numerous times, the sound guy has a huge influence on the issue of good or bad sound. 

Having actually done live sound for large venues I can tell you that at best it is extremely difficult, trying to work with the acoustics of the venue, the artists (onstage monitors are a completely different mix with different objectives from the house mix), the road managers who love to backseat drive the mix, often with little or no regard for overall sound quality. Add to that most sound guys have little or no formal training in sound reinforcement, architectural acoustics, or even basic listening. There are notable exceptions, many already mentioned, the last gig I helped produce was in the chapel at Bastyr University outside Seattle. We hired Morgan Sound for the job, and when they learned the venue, they assigned one of their 'A' crews. Bastyr Chapel is long, narrow, tall and very reverberant. It required 4 speaker sets, the second set delayed about 60 msec  to account for the distance from the primaries. They pulse tested the rig to set the delay, and only eq'd using the singer's voices to get a natural sound. The result was exceptional. These guys were pros. More recently I heard the Mavericks, and their opening act sound was hideous, both muddy and harsh, basically a mess. The mixer clearly had no idea what they were doing. The Mavericks were a revelation, same gear, same venue, different hands on the controls.  controls. They sounded great, and the volume was appropriate. 

Thevbest recorded example of how tough live sound can be is the the track "Stay" from Jackson Brown's " Running on Empty".  At one point you can clearly hear the system being pushed hard by the performance and the vocals start into feedback, only to be caught just in time by the monitor mixer and pulled back, into control. Believe me, because the show was being recorded, the mixer saved himself an uncomfortable post-show moment, and maybe even got a thanks for that. The result on the record is the the band, the vocals, and the system all giving everything they have for the music, and it's there for all to hear. Some days it just all comes together like that.