A valid view Steve but take another massive post '77 tune actually big at the same time as Betty Boo - Rita and Tiarras. That was out there for the returnees to hear on CD. Even those Goldmine 'This is Norther Soul' LP's which had Tommy Navarro, The Admiration and Sam Fletcher on I think will have given some prior exposure to some tracks.
Using your logic those tracks (and others like Doug Banks, Howard Guyton etc) would be unfamiliar too but they have all been dancefloor favourites at one time or another favourites since the mass return started in the mid 90's.
The difference with Betty Boo is it was never a part of those compilations precisely because the people putting them out couldn't risk it.