The "Perennial Philosophy" school of thought [1] says that people rediscover these ideas over and over again. It takes a particularly prophetic individual to stumble over them de novo, but once the idea takes root it spreads quickly.
There's a great quote from William James on the cycle of religious discovery, diaspora, corruption, and rediscovery, but I can't find it.
Not sure if this is the one you're talking about, but it rang a bell. I saw it in a Tony Robbins book most recently and then repeated in a book about TV addiction.
“First, you know, a new theory is attacked as absurd; then it is admitted to be true, but obvious and insignificant; finally it is seen to be so important that its adversaries claim that they themselves discovered it.”
- William James
"First, it is ridiculed.
Second, it is violently opposed.
Finally, it is accepted as self-evident."
There's a great quote from William James on the cycle of religious discovery, diaspora, corruption, and rediscovery, but I can't find it.
[1] https://en.wikipedia.org/wiki/Perennial_philosophy