Klyde O'Scope
Chameleon Enthusiast
I think it's more likely because it's a local thing, and the local stations are paid to publicize local events.I live in Central California and whenever the San Francisco Symphony Orchestra is playing with a modern band local DJ's make note of it. When Metallica plays with the San Francisco Orchestra it is big news. I think this is most likely a favorites thing (and Metallica songs play great with an Orchestra) not the band members are all dead thing.
Metallica is a local band; formed in L.A. but based in S.F. for most of its career.
https://en.wikipedia.org/wiki/Metallica
From that POV it may seem like big news, but for the rest of the country it may not be more than a blip.
Band members being dead applies to some bands that played with orchestras going back to the '60s on, e.g. The Who (Tommy), whose original members John Entwistle & Keith Moon have passed.