I agree it is 2nd but I don't think it is "very close" if you look at the numbers. The crappy NFL games draw a lot more than the crappy CFB games but I do think there is one reason for that. The NFL doesn't broadcast as many games on a Sunday (or Thursday or Monday) so they force the NFL audience to fewer games. That increases viewership on a per game basis quite a bit.
I asked one of those NFL fanatics the other day why he preferred the NFL to CFB. One of the reasons he went on and on about. The length of the games. Both are four 15 minute quarters but it appears CFB games are much longer in totality.