Off the top of my head - you may eventually see suits against the NCAA, but it's not nearly the same dynamics happening there as with the NFL.
In the pros, the players are employees of their teams which in turn participate in the league. The football field is the workplace. This is important under the law, which has developed concepts and rules that define the employer/employee relationship and the employer's duty to provide a reasonably safe workplace. When you add to this the league's history of denying the long-term implications of concussions, and the very deep pockets - you can see why the plaintiffs have pursued litigation.
I don't think it's quite the same situation in the NCAA. Though the NCAA may govern college football, I don't know if a player would as easily have a direct claim against the NCAA rather than the university at which he played. Though, yes, the universities likely have what are ultimately similar duties to the players regarding reasonable safety that, I don't think the dots are easily connected there. Plus, public institutions may have immunities or heightened standards for liability that private organizations (like an NFL team) don't have. There are also far foggier issues of damages for college players (much easier for an NFL player to demonstrate real financial damages than a college player who is likely limited only to medicals and some disability compensation). Plus, I think the NCAA has a far better record on its acknowledgement of the concussion issue (it began changing rules in the 1970s).
Not sure if this is the full story, just postulating on the likely differences between pursuing the teams/league for a pro player's concussion case versus pursuing the schools/NCAA for that of a college player.