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Bitcoin coming into existence was easy to predict, all the tech existed at the time and it was only a matter of time before someone combined them. What was not predictable however, was bitcoin's success.

Same thing goes with pandemics, we can always predict they will happen eventually, but we can never be certain when or how bad they'll be. COVID-19 luckily has been mild compared to previous major pandemics like the 1918 pandemic, but it could easily have been much worse.