It's very hard to justify copyright in 2026 over music used in a 1980s TV show. Shows were aired once or twice (summer reruns), with additional syndication runs for particularly popular shows, and that was it. Nobody expected to make a dime from a show 40 years later. Copyright has grown absurdly out of proportion of the economic reality for which these works were originally produced.
Probably? But to devil's advocate here, I grew up watching reruns in 1990 from the 1950s on Nick at Nite or UHF stations. You could make a case that not only the actors but bands who allowed music to be used would deserve residuals, and with reruns that worked fine. The format change from TV to DVD and then to Streaming is what blew it all up.
Home video releases of whole series weren't envisioned until basically the 2000s. Most TV shows that did have releases on video would just pick a couple good episodes at a time, and sell those. A reasonable job to track down a half-dozen rights holders, and if you couldn't find them or get the rights, I assume they'd just pick a different episode.
The way the original terms were negotiated, the rights were just licensed specifically "for television" because that seemed like all that was needed, and the amount of work to locate each rightsholder to renegotiate is just astronomical. Thankfully now every show is making sure to get rights for streaming (and physical media... Right? Right?) but it's a shame what happened to everything from the 1970s-1990s. Only piracy can save us.