I think the mistake that many of you are making is the assumption that U2 has much desire to cater to the "hardcore" fans that petulantly demand shows comprised almost entirely of obscure songs. Before I continue, I've seen a ton of shows and have my own list of rare songs that I'd love to hear. However, I know that I and many of you comprise a tiny fraction of the people that attend these shows. Sure, there may be 1500 crazy fans camped out for days for the GA line, but what about the rest of the stadium that are more casual fans, yet fans nonetheless? Do they deserve to be slighted of the songs that represent U2 to them?
I'm in the minority of hardcore fans I guess, but I would be deeply disappointed by a setlist without Streets, WOWY, SBS, BD, etc. Yes, I have seen them every single show, but they belong in each of those shows as the songs that define the band. I feel that the 360 setlist is an awesome combination of required standards and rarities. On Vertigo when An Cat Dubh / Into the Heart was played, there was an obvious drop in crowd participation. Obviously the fanatics were thrilled, but the "average" fans (who, again are probably 75% of the audience) kind of zoned out, which leads me to my point.
U2 is legendary for the power and intensity of their live shows. A large part of this energy is absorbed by them from the crowd. What is the better bet to generate this atmosphere, pandering to setlist elitists or the entire stadium?