Oldies are from the 80s now. Elvis is just too old. Advertisers don't want to market to the 70 or 80 year olds.
Linda Ronstadt is now oldies, with John Cougar, Phil Collins etc.
Elvis got his fame in the 50s and 60s. Was already established. Even though he was a king in rock and roll. He seems to be kinda a decade older than the Beatles, Stones, Mellencamp, Springsteen. The 80s are now the oldies.
I guess I am lucky. I have Alexa on my phone, When in the car I bluetooth it to my radio and tell it to play whatever artist I wan't.
I told it to play Elvis after your post and there they came. If I didn't like I just said play next. Never bought his music but he was a fabulous singer. Great voice.