"The band I like only played North America ONCE on this tour. Don't they know that they owe me?"
Seriously, cry some more. We get it, you're not an IM fan. No one cares.
They weren't going to tour this summer anyway, largely because they just played a North American tour.
Also, yes, DT can easily carry a tour by themselves, but Iron Maiden is one of the biggest touring acts in the world. This is an incredible opportunity for them, and they would have been insane not to have agreed to it.