But black swans always look obvious in retrospect. There were always reasons to believe a given black swan would happen, it's just that those reasons were ignored beforehand. The possibility of a plague was well known, but besides people in the medical field there wasn't much thought put towards them.

Heck, I well knew that medical experts were predicting a plague, but if you'd asked me in 2019 what the next black swan would be I'd have guessed catastrophic climate change.