Hurdle, there is a whole lot of truth in what you just said! There are a number of factors, but this one may have just nailed it.
Especially in the 1980s and 1990s, Nebraska had become one of very few programs successfully running the option. Because of that fact, there was not a whole lot of competition when it came to securing running-type quarterbacks, and they landed some outstanding ones, from Turner Gill (Texas) to Tommie Frazier (Florida), and a number of other ones in between. Another factor that made their option attack a recruiting boom was because a talented high school running back knew he was going to get 25-30 carries per game if he won the starting job at Nebraska. Hence, they were able to land stud running backs, guys like Mike Rozier (New Jersey). They knew they could get 250-300 pound corn-fed Nebraska kids to come to Lincoln to fill out the offensive line, so from a recruiting standpoint they had a pretty sweet deal. They knew home-grown kids would fill in the line (by and large), they knew their only real competition for the running quarterback was Oklahoma, and they always had four or five running backs who could start anywhere else in the country.
From a defensive standpoint, they were able to get great defensive players because they were a perennial power who played in a January 1 bowl game every year (when playing in a January 1 bowl game actually meant something), they had some of the best weight/training facilities in the country, and the Blackshirts had gained a reputation for being one mean bunch of dudes (not to mention that Charlie McBride was one of the most well-respected defensive coordinators in the country).
There is no question that the uniqueness in what they did was a huge factor in their success. Other things certainly played into their success including Tom Osborne, the continuity on their assistant coaching staff, a long line of All-Americans and NFL players, being on television four to five times per year (before the proliferation of television coverage), a very loyal fan base, etc.

