I imagine there are countless of individuals that are very famous within some region, but little known outside of it. It's not easy to have global recognition.
The hit in question, the one that outsold any individual Beatles single was from 1976. That was a time when most people received news from around the globe in print, with most of those print publications being regional and a handful being national. Something similar could be said for radio, though some people could hear stories from afar on the shortwave bands. That was more the exception than the rule though, typically of greatest interest to those who wanted to hear voices from their homeland or those keenly interested in learning about the world. (Even then, language was typically a barrier. When it wasn't a barrier, most of the stations were propaganda machines.)
Even though your claim undoubtedly remains true, at least we live in a world where those stories can leak out.
> Many of the artists in the list below have both streaming and sales included in their totals.
At best, this is a misleading comparison of apples and oranges. At worst it's an attempt to prop of streaming as actually compensating artists when they basically don't.