The NFL has those because of congressional antitrust exemptions—I think they were written in the 1950s. That’s why we didn’t have NFL on Friday nights or Saturdays—the law protected college and high school teams from pro competition
You don’t need an antitrust exemption to have a pro league with a collective bargaining agreement, though.
There’s some carve outs for TV agreements that I think cover the big 4, but there is no NHL antitrust exemption law that lets them negotiate with the players union that I know of.
The big difference there compared to CFB is that it’s a union and a league negotiating rules together and coming to an agreement instead of a league dictating terms for labor and colluding to (nominally) punish schools that break those rules with no actual input or other options for the players.
I think CFB could do that today but they’d have to admit “this is a big-money professional enterprise” and they still aren’t willing to do that. Despite the SC making it pretty clear that if it looks like a duck and quacks like a duck and makes everyone else involved millions of dollars, then you can’t claim “amateurism” as a fig leaf. I generally agree with your take that the Gorsuch decision was less aggressive than what Kavanaugh sounded like he would support and probably was part of a “give them some time to fix it themselves” restraint. Oops…
The proposed division split probably doesn’t even help that much - how do you enforce that the lower division doesn’t have big revenue or player compensation without getting into the exact same problem?
Edit: you can probably also have a free for all of contracts for players, but the collective bargaining part is how I think you get restrictions and parity-promoting rules across the finish line.