I think this is very interesting and it sheds light, but there are some different variables to account for when reading.

Such a long layoff opens up almost all songs, which then I think they tend to "lean" on their strongest ones which is why it doesn't rate as high. There were also a lot of new songs this year since last Dicks that they wanted to showcase, which isn't what some people want to hear. Also, the graph makes 2019 appear low, but rating close to a 4 is still solid imo.

I do think them playing together closer to the shows helps and I am all for a 2-leg run of June and August again or something similar where Dicks really is the summer tour closer and not a one-off.