Re-writing musical history?

This may not mean much, but I've been noticing lately how little '60s/'70s Soul and old-school R&B gets played on the Seattle area's two oldies stations, KJR and Q104.5 -- the two places you'd think those old hits would have a home, right?
I almost always hit the radio dial at nights when I'm working -- before giving up in frustration at the Same Old Stuff and slapping on a CD. So what I'm about to outline has probably been coming on for awhile.
Over my weekend, I ended up listening to these two stations a lot -- for more than six consecutive hours in the afternoon and evening a couple days ago, bouncing back and forth when things got boring.
And during those six-plus hours, I never heard a single old hit song by any African-American artist. Not one.
No Stevie Wonder, Marvin Gaye, Al Green. No old Motown. No Aretha, Sly, Temptations, Four Tops. No Atlantic soul, no Stax. No Sam and Dave, Otis Redding, Wilson Pickett. No Donna Summer. No Supremes, even. No Jimi Hendrix, who was from Seattle. Not even Chuck Berry or Little Richard. Not even Michael Jackson.
I'm sure this was just an oversight. I'm sure it's not some sort of informal, unintentional white-supremacist radio-programming thing.
But still.
There was LOTS of white bands and Album Rock -- lots of Police, Eagles, Zep, Skynyrd, Fleetwood Mac, Beatles, Queen, Bowie, Def Leppard. Almost all of it sounded pretty good, too. KJR will even play awful hair-bands from the '80s.
But there was no Black music. I've read critics who claim rock and roll is a "white" phenomenon, but really....
KJR did at least play K.C. and the Sunshine Band's "Get Down Tonight," which I hadn't heard in YEARS, and which sounded pretty good. KC was at least an integrated band.
I'm not trying to make a specifically racial point here. But I'm wondering when oldies radio (and Album Rock radio) apparently decided to -- forgive me -- whitewash the last 50+ years of pop music.
I checked-in with the radio several times tonight and finally heard the Emotions' "Best of My Love" from '78, and it sounded just fine. But that's the only classic Soul/R&B tune I've heard on the radio in days. Usually I can at least catch "Sittin' on the Dock of the Bay" or "When a Man Loves a Woman." And I was surprised not to hear "Drift Away" or "I Can See Clearly Now" over my weekend.
Not saying my ear's glued to the radio 24/7 -- far from it. Most radio is so boring I want to scream.
But could this be another example of how our memories continue to get whittled-down to the same 200 oldies that get played over and over until we can't take it no more?
KJR is so predictable you can almost set your watch by when they'll play "Stairway to Heaven" (twice over the weekend), "Sweet Home Alabama" (also twice), "Smoke on the Water," "Hotel California," etc. KJR plays Sly's "Hot Fun in the Summertime" in a commercial about having "a summer full of hits." But they won't play THE SONG.
Yeezus, no wonder everybody's gone to iPods or their own playlist on their smartphone or whatever.
The list of artists I mentioned above that I HAVEN'T heard lately are all part of rock and roll, and part of our shared musical heritage, dammit. It's shocking that they aren't better represented by two stations that claim to play "the greatest hits of all time."
I'm sure this wasn't done on purpose. I'm sure it was just a lapse. Maybe I was on the wrong station when Al Green's "Let's Stay Together" got played. I just missed it.
But it looks like if I want to hear "Land of a Thousand Dances" or "Sweet Soul Music" again anytime soon, I'm gonna have to buy the CD's.
It ain't right.
And this observation is coming from a white guy from Idaho, so you know what I'm bitching about must be pretty freaking obvious.