Lets take a look at the past ten national title teams in order from the most recent;
Florida State
Alabama
Alabama
Auburn
Alabama
Florida
LSU
Florida
Texas
USC
What do they all have in common? The states all have coastlines with a warm year around climate, and the five states all rank in the top seven in the graph Abdullah the Butcher provided (maybe not the most reliable). Geography plays a huge role, in the fact that the state of Mississippi is sandwiched in the middle of Texas, Louisiana, Alabama, and Florida. Weirdly enough, Colorado, Wyoming, Iowa, and Missouri schools don't seem to be anywhere on the list of National Title teams since... 1990. In the past 24 years one state that touches Nebraska has won a national championship. Name another national title winning team to come from a state that touches Nebraska. This forces Nebraska to recruit kids from California to Texas to Florida, as there clearly isn't enough talent in the immediate region. With a coach like Pelini, who is a mediocre recruiter, it makes it tough to entice young 17 and 18 year olds, in the age of social media, to come to Nebraska.
Also, the SEC has the ability to recruit more efficiently today because they have won 7 of the last 8 national titles. Pelini can't walk into a recruits home and say; "We play against the best competition game in and out." Instead he has to say; "You would look good in a Nebraska jersey as we beat cream-puff A, B, and C." Recruiting is half of the equation, while coaching is the other. You have to be able to persuade a good coach and staff first, then have that staff recruit quality kids to fit their system and style. We have recruited many five stars. It would be interesting to know the reasons they did not choose to come. My guess is if you took the Nebraska facilities, campus, and stadium and placed them in Starkville, MS, our recruiting would only get better.