I think there’s a catch, which is lag time. Even under pure capitalism, if the market doesn’t believe the money will last, prospects aren’t going to risk their careers given the training lead time required.

In the US, ATC are federal employees, aren’t they? So they are regularly furloughed, too. In the current political climate, facing the wrath of politicians doesn’t seem that unlikely, either.

The US has form in this area, too: https://en.wikipedia.org/wiki/1981_Professional_Air_Traffic_...

Even if the federal government were to “pay up”, they cannot be relied upon to honor favorable contract terms since they also have the ability to change the law.

Conversation about how there’s a critical shortage of ATCs is at least a decade old, and likely older. “Best time to plant a tree” and all that.