^^ the suggestion that "50 years ago there were very few public courts in the USA" is absurd. I started playing as a small kid 50 years ago and courts at high schools, middle schools and public parks were not only abundant but easier to access than years later because the tennis boom of the 70s had not yet begun. What WAS available to the affluent though was quality instruction, which could not yet be found easily in public settings.
"Where's the REST of me?"
Ronald Reagan, in "Kings Row"