The general music buying public see U2 as cool and Bon Jovi uncool, simple as that.

U2 never had poodle perms and dressed like Transvestites, U2 never wrote songs about laying hands on people or bad medicine. They wrote about things that matter and every album was different while still maintaining quality.

U2 live are always an ever changing interactive band also, Bon Jovi just seem happy to pick up the money and run these days.

Probably the best live performance I've seen on Youtube