Simple explanation - its a rip off !! Too many punters have been burned in the past and they have smartened up.
Going through a tour/packages costs a bomb. And that's with Category C seating ! Trying to organise your own tour, and lining up quality tix & accomodation in tiny, long booked out cities is a logistics excercise akin to planning the Normandy Invasion. It really is hard to extract quality from a tournament that is largely filler.
And for what ? There's little entertainment value in the World Cup - remember the up & under fest that was the 2007 RWC ? Teams get conservative and whistle blowers dominate. In NZ at that time of year there's also a good chance you'll get soaked in the freezing cold. I am not shelling out $10K to watch stodgy penalty goal exchange contests in a shitty stadium, subjected to subzero temps and torrential rain. I paid something like $1200 for 2 tickets to watch the RWC 2007 semi-final. What I thought would be an epic Australia vs NZ clash turned into a limp England vs France kicking comp. Never again.