I'm not a lawyer, so I'd defer to any one of the many that we have, but if I was making the argument on Sac's behalf in a court of law I would argue that competitiveness on the field is not at issue. At issue is the NCAA is a monopoly (which is true), and they are creating a barrier of entry to the FBS that wrongly denies the financial gains that Sacramento State believes they will achieve. Through their violations of the Sherman Act, and both the letter and the entirety of the spirit of antitrust regulation, the NCAA is wrongfully denying Sacramento State the ability to make this move. Regardless of whether the NCAA, or the public, likes it, the NCAA has no antitrust exemptions and cannot continue to hold this barrier of entry that causes clear and direct financial harm to their University.
I'm not saying I want that to happen or that I want them out of the Big Sky, I actually don't at all, but I think that would be a tough argument for the NCAA to fight without that antitrust exemption.