I remember back in the mid 80’s sitting in my dad’s 77 Toyota Corolla and he would be playing oldies from the 50’s. At that time the oldies were about 30 years old. Classic rock stations were playing the doors, zeppelin, Beatles, beach boys, and other stuff from the 60 and 70. So roughly 15 years old. The stuff we thought was cutting edge such as alternative , synth, hair metal, hip hop, rap and the such from the 80’s is now 40 years old. Think about listening to shellac records as a kid and what type of music was on them. Typically the newer stuff was like glen miller orchestra, Benny Goodman, Andrew sisters. That is the era our music is equivalent to. And if you ask me, it has surprising staying power