Funny how things change over time, but really just move from one place to another when you dig a little deeper.
Admittedly, I wasn't a big fan of Talk Radio in the Sixties. My understanding from what I've read is that what Pat Burns did at CJOR that cost the station its license in the mid-1960s was mild compared to what we are discussing here.
So, I think it would be fair to say that broadcast regulations on both sides of the border (FCC and BBG) kept the lid on what talk show hosts could get away with in the 1960s.
The closest thing to what we see today was buried in among the paid religious programming, usually in the middle of the night. The late Brian Williams was an avid Vancouver DX'er in the late 1960s and told me, at the time, what he was hearing in the middle of the night. He was not up at that time to listen to these guys, but knew which ones had long pauses where he could hear another station underneath. Most notably a Russian station on the Pacific Coast on the same frequency as KTW in Seattle.
The one name that I still remember Brian talking about is: https://en.wikipedia.org/wiki/Carl_McIntire
A quick read indicates, as well as buying time for his program on a lot of U.S. stations, he lost the license to a station he owned and took a brief shot at running a ship-based pirate station.