Why does rock concert sound suck?

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.

It's too bad that a good home hi fi set up can & often does sound better than many live rock concerts. Small venues (less than about 400) can still sound really good but the larger venues rarely do; very hard, upper midrange peaky, boomy loose bass & shrill highs. This is the worst example of what the solid state / horn combo can do if poorly done. 

IMO, here's the reason & when I was in pro sound reinforcement, this wasn't the case. The use almost universal use now of arrays from just maybe 6 speakers to upwards of 20 powered by high powered, well built, very reliable but sound crappy class D amps. The theory of the array is to try to create the same sound balance for every seat in an arena w/ minimal "sweet spots". The benefits of the pro class D amps are obvious but sacrifice a  lot. Almost Every instrument in a band is now run through this stupidly loud, hard as hell sound system & the beautiful magic of stacked Marshalls or Fender tube powered amps is lost.

I saw the Grateful Dead many times in the 70's, never w/ their short lived, giant "wall of sound" system ,but w/ a very good one that included about 30 Macintosh 2300 amps, & piles of Altec & JBL speakers. The sound was truly dynamic, meaning loud only when it was supposed to be & not continually, crisp, clean & beautiful. It was the same w/ many great shows I saw at Radio City Music Hall in NYC back then w/ many great bands. If you had a good seat, fantastic sound & if not it was ok. Today, its pretty bad in any seat but arenas are still filled so no one seems to care.  

I guess the sound today of rock concerts is on par w/ the music itself...... loud, bland, boring & bordering on unlistenable. 

Thank you @wolf_garcia ​​​​@panzrwagn for sharing and validating that yes, it can be done.  

@sparksgja "Lots of washy echo, clear yet layered guitars, keyboard synths and a bass so firm my mid chest vibrated (and I kept telling myself to buy a subwoofer). It sounded for all its loudness completely involving and visceral."  - sounds like you got the War on Drugs exactly as you should have.  Love that band.  
 

Honestly (and not to be mean) the rest of this thread should be followed up with a "Get off my lawn" type of complaint.  Know the venue, know your band, and set expectations accordingly.  

Sincerely, fellow grey haired gentleman.  

I put my money on the venue/structure and the design/build in the bad acoustics. Where I come from is a great example, in Edmonton Alberta, Rodgers Place(home of the NHL Edmonton Oilers), is perfect venue for concerts in its design and sounds awesome. When they built the building concerts/music was part of the design/build. Now go south down the highway to Calgary Alberta, and the Saddle Dome(home of the NHL Calgary Flames), the building is shaped like a "saddle" and every concert I've been to there, the acoustics suck...bad, really bad! 

Blaming Class D phased array speakers is silly...a good sound mixer can make nearly anything work well. Also, now that in-ear monitors are nearly universally adopted, the on stage levels can be anything. A little history: Piles of Altec A7s or similar JBL boxes were standard (often with Mac amps) until maybe the mid 70s when Clair Bros. boxes (or similar) were introduced. They could have JBL 15s with other JBL horns and tweeters in a single box often stacked or flown)..often powered by piles of Phase Linear amps...anybody think those amps sounded better than modern Class D arrays? No they did not...the days of super loud crowd blasting sound had arrived.