I think it is the time. At 6, a lot of people are just getting home and eating dinner, aren't settling down to the TV yet.I know Brit may just want to get home at a decent hour, but moving his show to 7pm would be a huge ratings bonus. Most nights I don't get home in time to catch his show at all. Damn this conservative work ethic!
I catch the last 30 of Brit when I get home. The TV goes on to Fox as soon as I walk in the door. By the way I went to the same high school as Shep Smith!