"So how did arguably the most popular idea on the internet end up on the scientific ash heap? For that matter, how could such questionable research migrate from a journal to a viral video to a best seller, circulating for years, retweeted and forwarded and praised by millions, with almost no pushback?"

That's easy.

1. Videos and books aren't peer reviewed. In fact, books and videos by scientists usually are not even about the science. They are about self promotion.

2. Peer review isn't the gold standard of truth. At some level, it's political. At another, it's just three or four people arguing about what they believe.

And don't forget...

0. A single paper has roughly as much chance of being wrong as of being right, even without methodological issues. Which all research has.

But also...

-1. The power pose thing told people something they wanted to hear. Piltdown man and cold fusion did too. And that recent thing with random cells + lemon juice -> stem cells.