None of that changes the copyright situation. Content doesn't become public domain because someone dies or the company goes out of business. The ownership of that content is transferred to new entities.
Guys, here's the thing on old time radio:
Any broadcast created before January 1, 1978 was covered by the Copyright Act of 1909, not the Copyright Act of 1976.
The 1909 Act provided for 28 years of protection and (IF filed for, one additional 28-year extension) before a copyrighted work entered public domain.
So---IF a broadcast from 1969 was copyrighted AND the copyright extended in 1997, that extension expires this year.
Most never opted for the extension past the 28-year mark.
Everything from the so-called "Golden Age" is in the public domain, with the exception of any copyrighted and licensed musical performances, which were addressed differently by the Copyright Act of 1976.
