See, I'm the opposite. College basketballs format is set that any solid team "can" win a national title. UConn won it last year as a 4 seed. Tell me the next time a non top 12 team has a prayer of winning a college football title. No football team can be "good" and hope for NCs. You have to be of a certain elite breed. College basketball, any good team can win one.
I'm not sure it's all that different.
I think you're talking about "top 12" in football, but there are only 130ish teams. In basketball, there are >300, and the rosters are much smaller, so I'd venture the equivalent is about the top 24 teams as talent is more spread around... 24 would coincidentally point to about the top 6 seeds.
Oh, look at the history... Only one 6 seed, one 7 seed, and one 8 seed have won the thing since the modern tournament began in 1985. In fact, since zero 5 seed teams have won it, that means that the other 35 tournaments in history have been top 4 seeds (top 16 teams).
I think the modern basketball tournament is actually quite similar to what the CFP tournament would be if it were, say, 24 teams. The bottom 14 teams would effectively be "cannon fodder" for the top 10, because although they might win a game or two, they can't keep it going forever against the real contenders.
There's IMHO slightly more variance in basketball than football... But it's not like St. Peters, who made the first 13-or-worse seed appearance in the E8 in history, actually had ANY chance to win it all.