What type of retaliation could be expected from the NCAA? If all college hockey programs unite under the umbrella of USA Hockey, what impediments to competition may arise concerning NCAA governance or structure???
Do you believe that Illionois or Iowa would pressure the Big10 to levy a fine against the Wolverine football program because the school's hockey program broke away from the NCAA? Do you really believe they give a single iota of thought to it??
Firstly, "if all college hockey programs unite" is about as big of an "if" as "if all countries stopped fighting we'd have world peqce." Sure.... but not going to happen.
Second, you named Illinois, which is part of the Big Ten, which specifically created a sport-realigning hockey conference in an attempt to make money. You'd better believe that the likes of Illinois and Iowa and the Big Ten would absolutely be furious at any hockey program trying to go their own seperate way. They'd arguably the biggest haves to be the most against such a thing, and would be on board with any kind of punishment possible.
As for what retaliatory measures that conferences and the NCAA at large could implement, take your pick. They all make money by making sure that their members toe the line and don't rock the boat too much. Fines, sanctions, loss of scholarships, and any kind of legalese written into media contracts absolutely would be hefted against schools, big and small, for attempting to break away even in relatively smaller money sports.
And while hockey is still second fiddle to the likes of football and basketball, it still makes assorted conferences and the NCAA money, and is deemed important enough to get actually reasonably good amounts of ESPN coverage during its tournament. It's not like we're talking about things that the NCAA doesn't care about, like minnow-sized club programs or sports that the NCAA doesn't seem to care about enough to make a varsity product, like shooting, bowling, and boxing, which have college programs outside the NCAA that some NCAA members have programs for as well.