With the tremendous change in SF from the early 70s to present, I'd wager many of the folks who might have nostalgia for the early 70s have largely left the Bay Area itself.
That's logical, but I also know a lot of people who are Bay Area lifers.
And there, my friends, is the essential essence of this argument. Those "lifers" are increasingly pushing up daisies poppies in Colma with each passing year.
Not to get too solipsistic about it, but I thought I would be in the Bay Area for the rest of my life, too, once I got there at the end of the last century. Then came increased fire danger, days filled with smoke including one day when smoke got trapped in a temperature inversion and it stayed dark all day, power shutoffs whenever there were red-flag conditions, worries about what we would do when The Big One (earthquake) finally hit, weariness with a house that offered nasty surprises every time a repair was attempted, high taxes without the services that should come along with them, poor-quality local governmental services, and so on. So we started looking elsewhere for our retirement. We didn't want to have to be dealing with all that stuff when we were in our 80s. Yes, Colorado has fire danger, too, and we carefully avoided neighborhoods where that would be a problem. Yes, there's snow in the winter. But it's not that bad, not like Chicago or Boston. Yes, I miss some things. I miss our friends. So we try to make sure we get back there every so often. Regarding media, I miss KCBS and KTVU. KUSA(TV) is good, too, though I wonder how long it'll last; in radio, KOA is a poor substitute for a news/talk station and is getting worse, while Colorado Public Radio tends toward featurish material. But there's more to life than consuming media. Our quality of life in Colorado is mostly better than it was in the Bay Area. Twenty or even ten years ago, I wouldn't have said that. But so many people have crowded into the Bay Area, and so much money floats around and chases limited resources, that it's now a better place to visit than to live.
We have a little sport of looking out for California license plates: that's probably the most common out-of-state plate in Colorado. Some of them even have up-to-date registrations.
I haven't looked it up, but I suspect there's still a net gain of population in the Bay Area, but those are people likely not to care about radio of any sort, or even linear TV.