It's definitely possible. There are hundreds of Div1 schools all over the country, thus creating fans in pockets where the NBA and NFL can't reach. There's more grassroots and geographic support for college sports than professional. Thus, even though I don't watch or like basketball very much, I would support the position that it could be the biggest sporting event of the year for "the whole country".

The Super Bowl, often one of the most boring games of the whole year, is an event that draws a great deal of viewers and participation all over the world, but even I only half-watched it this year--or at least made sure I was around for the commercials. It was probably a hit with people on either coast, but was virtually irrelevant for us in "flyover country" (please note the sarcasm).

tyler