Please, just because U2 took 5 months before they toured ATYCLB doesn't mean that it took them 5 months to prep for it. Most likely they designed some sets and put together the tour calendar during the Nov - Jan months. Then began rehearsals in late Jan through March. Tour started March of '01. In 1987 U2 released the Joshua Tree in March and began the tour in April. I believe Popmart failed so spectaculary on its opening night (I'm convinced) because the material U2 recorded didn't lend itself to a live environment.
This new album is probably pretty much in the can (maybe), and so by the time they send the tapes out for mastering (best guess November) and then began rehearsing for the tour (February?) and then release the album (March..definitely) they'll have nearly 5 months since album completion to tour their new album. I believe the tour will start in April.