Now I find this 2008 Steve Hsu blog post:
After the talk I had a long conversation with John Preskill about many worlds, and he pointed out to me that both Feynman and Gell-Mann were strong advocates: they would go so far as to browbeat visitors on the topic. In fact, both claimed to have invented the idea independently of Everett.This is heresy. Feynman and Gell-Mann wrote a great deal about quantum mechanics, including about interpretations, and as far as I know, neither wrote anything positive about many-worlds. They did not push it in lectures either.
Preskill coined the term quantum supremacy, and quietly admitted support for many-worlds in a recent interview.
Weinberg died without endorsing many-worlds, but he was heading in that direction, with more and more denunciations of Copenhagen Interpretation in his old age. He discusses many-worlds in this 2016 video, and says he finds it hard to stomach.
What goes here? Is many-worlds an underground physics cult that many or most physicists belong to, but are embarrassed to admit publicly?
I don't know. I can imagine physicists being closeted Christians or Trump-supporters, as these beliefs would invite derision from their colleagues. But can the same be true about belief in our world being one of many worlds, which are all described by the unitary evolution of a universal wave function?