no, i don't see how it could be deemed a failure. they've sold out every show, and gotten mostly glowing reviews from the media. fan opinions are largely positive, though some think it doesn't compare to elevation.
i, for one, think it's a great show. it's not Zoo TV, but then again, nothing will ever match the spectacle and vision of that tour. it's much better than Popmart, in my opinion. to me, Popmart was lacking something... i can't put my finger on it. in some ways, i prefer Elevation- i think what i miss most about that tour is the novelty of GA, and the community that was formed while waiting in line for the show. yet i like the 'whole package' of Vertigo better- it's more theatrical, better lighting... i also love the old songs (Electric Co, An Cat Dubh, Gloria, etc). and the Zoo Set is fantastic. it's probably a tie between Elevation and Vertigo for me.
the Vertigo tour is a success. it might not be U2's best tour, but it's far from their worst.