While I don’t disagree, I’ve seen that many “oldies” format radio stations have shifted away from that definition in recent years. IME, most “oldies” stations no longer play anything pre-Beatles, and tend to now focus on the late 60s through the mid-to-late 70s.
Yeah, they seem to be refining it further and further. Sirius/XM even has stations dedicated to one artist, or one particular style, such as disco. “True” oldies stations play nothing but pre-Beatles, or will maybe include a bit of that genre (Stones, Byrds, Hendryx, etc.).
I used to be a huge fan of groups/artists like The Limelighters, Buffy Saint-Marie, The Clancy Brothers, Ian & Sylvia, etc. That was more of a 60s folk movement, rather than part of the old artists like Guthrie.
I was station surfing and heard a U2 song and stayed on that station to listen. Then came a station break - I was listening to “Your Favorite Oldies Station.” I had to pull the car over and let that sink in for a minute before I could drive off.
Classic Rock, as a radio format, spun out of what used to be known as “album-oriented rock”. While most “classic rock” stations do, indeed, mostly source their music from artists from the 60s and 70s, there’s a definite focus on harder and progressive rock, and rarely will you hear “pop” songs from those decades (unless they’re from artists who fit into the previous definition). And, some classic rock stations will extend the time frame for their playlists into the 1980s (but, again, mostly for artists which were already active in the 1960s or 1970s).
Oldies stations, on the other hand, will typically play pop songs (often defined as top-40 hits) from whichever time period they’ve decided to use. 20 years ago, Oldies stations played songs from the birth of rock and roll (mid-50s) through the early-to-mid 70s. As noted earlier, many oldies stations now play little, or no, music from before the British Invasion.
If you’re hearing Tony Orlando and Dawn or The Supremes, you’re almost undoubtedly listening to an Oldies station, not a Classic Rock station. Conversely, if you’re hearing Jimi Hendrix or Rush, you’re almost undoubtedly listening to a Classic Rock station, not an Oldies station.