I'm sure Madonna's shows will eventually sell out, and I'm sure that most of those cities will add a second show, wether the first one sells out or not. Selling out shows doesn't seem to be as important anymore as extracting maximum amount of dollars from a market. The Rolling Stones had a 270 configuration in arenas, and most shows still had a few thousand unsold seats. However, the shows still grossed something like $4-5 million per night, so the unsold tickets weren't really part of the story. The Stones, Madonna and U2 are still THE BIGGEST draws in the world. That they can still perform like they do at those prices is impressive. However, the ceiling has been reached of what people think a concert ticket is worth.
The worst selling U2 show this year has to be Chicago 5, and even at that it's at least 80% sold. By show day, I imagine it'll be 90% sold out. It's not like some of the poorly attended Popmart shows, where there were 20,000 unsold tickets in the stadium. A couple thousand unsold tickets in an arena isn't a big deal, especially when it's 1 of 5 shows in Chicago. The first 3 are basically sold out, night 4 will probably be sold out by show day.
Yes, they thought they could get 6 shows in Chicago and 8 shows in Los Angeles, and they have fallen short of those expectations. But really, most of the shows will be sold out. Shows like LA 5, Chicago 5, Boston 4, Montreal 4 might have a couple thousand unsold tickets, but it'll hardly be noticeable when you're actually there. If U2 were charging Vertigo Tour prices right now, all shows would've been sold out by now.
I still think they might add a 6th show in Los Angeles, as unnecessary as it might be. A 6th show in Chicago on July 3rd would be a death sentence, but if they don't mind playing to a 3/4 full arena, they might as well go for it. The Grateful Dead are playing Soldier Field that same night (also July 4th and 5th), so that might put the Kibosh on U2's July 3rd Chicago plans.
Not sure how safe stubhub is from scammers though.
