The good old days weren't all that good. They were what they were. I don't know how you can't call any number of songs from the 50s, 60s and 70s not "disposable".? "Honey"? "I was Kaiser Bill's Batman?" Didn't even Phil Spector call his music "little symphonies for the kiddies"? He had no inclination anyone would be playing it in five years, let alone 50. Yes I love a lot of older music, but with a somewhat selective filter. I can give you the perspective of someone who grew up in a smaller town. We listened to the great, legendary CKLW by day (pattern change and PJB eliminated them at night). Great as they were, my classmates in junior high would have been hard pressed to name the daytime jock lineup in the Drake and just post-Drake era. In addition, we weren't about to be allowed to call Detroit long distance (by the way, if you did call The Big 8, you didn't talk to the jock, you talked to one of the Hitline Girls). We had WOWO which had great personalities and was the default choice because of signal. Another Fort Wayne station signed on with top 40 in 1971, WMEE. We had a local top 40 for a couple of years, and I did have some of the experiences of seeing them broadcast from a tent at the county fair (bringing turntables, cart machines, the phone, etc.). I got to come by and watch one of the DJs at the studio. Too bad this format didn't last until I was old enough to drive, because I would have loved to work there. On the other hand, I had plenty of friends who were just as happy to listen to the automated TM Stereo Rock station. Folks were already starting to "engage" with other people by CB. Radio personalities (giving my market as an example) do still engage with audiences. The known personalities are everywhere, pumping gas for charity for one thing. My daughter was born in the 80s and does remember the music she liked in the 90s. I can definitely tell you my parents thought my music was disposable garbage.
Many of your complaints have nothing to do with radio, but the fact that your and my generation's experience wasn't frozen in time (if you had what you say you want, we'd be having this conversation in print). Radio can't operate as though it were 1967 and expect society to follow. I have co-workers who have titles don't even remember dial-up internet.