I'm not sure that this is the case. You have ten million opinions as to what was best and why and some heads will debate endlessly about what's the best.Why were Dead shows on the East Coast usually better than West Coast shows? And shows they in the south like Tuscaloosa Alabama 7-17-77 were epic
There are a ton of west coast shows that were fire.
The difference in show quality I feel just comes down to real life things we all face.. like Jerry being strung out and worn out at the end.. the bands drug use also had a big influence.. that and over that amount of time their music evolved.. like Jerries haunting guitar style at the end. Then you also have to look at what tour it was.. fall, winter, summer and spring usually had their own feel and songs.
But to tell you the truth I have no idea... I just get confused and then listen to the music play



