You can still see here how many people are looking for vB license. They just don't do their homework (google is your best friend), before they buy their first forum software. Most of us know which of the forum softwares is the better, but that is not enough. vBulletin has its name which sells. XenForo is just not so well known and that is the biggest problem and I have to agree with @@Elmore that it will take years until XenForo will reach the sales of vBulletin.