Lots of the places to download music only have newer artists.
And sme of the sites that have oldies, I find, have “sharers” that submit dummy tracks with the correnct running length but truncated lyrics followed by static. I guess this is to punish people for wanting free oldies, but some of the titles are not available elsewhere, except on expensive Time-Life CD collections.
I’m actually quite surprized that every owner of an old copyright isn’t rushing to get more cash out of a long dead album.
There are quite a few oldies artists on iTunes: The Coaster, the Drifters, Bill Haley, the Marvellettes, Everly Brothers, Chubby Checker, Fats Domino, Chuck Berry, Little Richard, etc.
It depends on whether someone put together a compilation album recently.
If you have Yahoo, they have Launchcast and they have EVERYTHING in the way of oldies.and you can download from there. They let you sample it then you can buy it if you want or you can customize your own radio station . You rate the songs which will influence what they play on your customized station. You make a list of the desired artists and it will begin to play them. Keep the songs you like, get rid of the ones you don’t like.