I don't reallly consider this a new tour since it will be the same. JT was because of a contract issue. Regardless, they have been in this much spotlight for awhile now. I think we're nearing the end, but the is not THE end.
I'd say another tour after this one and then that's it. But the next tour won't be for at least 4 years considering how long it takes them to make music or if it will be ZOOTV. But they won't end on a ZOOTV tour.