At this point it's likely up to Congress. Unless they do something, the Wild West is the only thing that would be legal.
The political geography might make a bill happen (with the caveat that Washington is a clusterf%@* & even things that really should happen aren’t happening): Republicans from SEC, Big 12, & Big 10 country will want to save the competitive fates of their universities’ football programs and Democrats, who are often more engaged in higher ed issues, can also portray themselves as fighting for the players (labor).
It will take an act of Congress because universities are battling to preserve the tax benefits currently generated by intercollegiate sports - namely, student-athletes generate (mostly) tax free revenue because their activities are deemed within the mission of the university while paying employees to play sports on your behalf would be a whole different venture.
The rules around this are embedded in the tax code, accreditation standards, state laws, etc. It’s a very complicated system that has evolved into a very particular behemoth. It’s exactly the kind of issue that Congress is best positioned to act on comprehensively - allow athletes to organize, rewrite relevant tax & accreditation rules, and throw in a host of other necessary updates. (The Higher Ed Act hasn’t been updated 2008, so there will be many stakeholders who’d want to append updates to a timely, high profile bill: Title IX, student loans, rules on for-profit schools, outcome reporting, etc.)
In the absence of legislation, these court cases are going to keep jolting the system in unpredictable, impossible to manage ways for the universities. And it’s going to cost a helluva lot more than a heavy lobbying effort in DC.
