As I understand it, the essence of the lawsuit was that the NCAA is violating antitrust law by infringing on Diego's right to earn money. Regardless of where he started, they argue, he should be eligible to participate at the money-making level of the NCAA for 4 years.
By that rationale, anyone that competes at a division not "opting in" to the pay-for-play model next fall should also retain 4 years of eligibility. An athlete could compete for North Dakota State or Furman, graduate, and retain 4 years of eligibility to go to a P4 school.
As a few pointed out, the judge just issued a temporary injunction and the matter is not completely settled, but this is just another sign the world of collegiate athletics is getting completely destroyed. There needs to be a complete overhaul, starting with an enforceable collective bargaining agreement that addresses transfer rules, seasons of eligibility, age limits, outside inducements (ie, tampering), etc.
As an aside, the message earlier this week from the Alabama AD asking fans to donate more money to pay players is sickening. Could the owner of the Raiders ask fans to donate money so they can pay Patrick Mahomes outside of the salary cap to come over from the Chiefs. I'm pretty sure that would not be allowed under NFL collective bargaining.