So, wait, was it that:
a) Most men worth influencing in the 50s had a mistress his wife didn't know about?
or that:
b) Most men worth influencing in the 50s understood that the guy calling him could persuade the wife that there was a mistress irrespective of whether there was really a mistress?
I don't know which it was.
But I'd say that you're seeing the trees, not the forest.
The major point of the quote was that there's a lack of courage in the world, the rest of the quote is just examples.
Take off every 'quote'! You know what you doing. For great insight. Move 'quote'.
And if you don't: