Athletes like playing for National Championships. If you're not recruited by an elite P5 school, another P5 school is probably worth the exposure for these athletes to get a NFL shot. If there are no P5 offers, the opportunity of playing for National Championship at a FCS school that gets fairly good national exposure is worth it for many athletes as oppose to playing for a G5 school that is going nowhere, hemorrhaging money and the only exposure they get is when they get pummeled by a school like Alabama.
Winners like to win, and those kids can do that at NDSU.