they were getting shorter and shorter, it looked likely to happen - the "europe" 2011 one was only 4 dates!
and yeah, as Ducko and SomedudeRemix said, I guess it's not economically viable, but on the other hand, the shed-load of big tours that go across the US now mean the band and their crew don't have to do it themselves, it's probably a bit less of a hassle and expense on their part to just say "yep, you do that stuff with accommodation, nation-wide promo and transport - we'll rehearse our songs and make sure our lighting looks pretty!"