Are non-compete clauses still a thing on New York radio? I don't know if any of those departed hosts can just go to another NYC area station right away whether they resigned or were terminated.
Absolutely. But not necessarily if contracts have expired...
Not a lawyer, but I believe under New York’s Broadcast Employees Freedom to Work Act (Labor Law § 202-k), post-employment non-compete clauses are generally banned for radio on-air talent.