I'd offer a much simpler explanation. The buzz around Bitcoin reached a critical mass where people at home with no knowledge of cryptocurrencies or blockchain technology suddenly got caught up in a bubble. As the interest increased so did the price so it became a feedback loop.

People saw their friends and coworkers talking about huge gains and wanted to get in on it. Coinbase allowed anyone with a smartphone and a checking account to buy Bitcoin which further drove up the price. Meanwhile the supply was only going up incrementally. So you had a huge swell in demand and no corresponding increase in supply. This resulted in the price increase.

Then when the supply of buyers slowed down there were more sellers than buyers and the price dropped. This is the most classic form of a bubble and I'm surprised that people are looking for alternate explanations, like the introduction of futures, which I find absurd. If it were so easy to predict a crash simply because you now had a vehicle to short it, everyone would have done so. There are ways to short most securities that are traded and yet not all securities collapse in value. The author cites two examples of extreme bubbles- the subprime mortgage market and Bitcoin in late 2017- and blames the crashes on the creation of vehicles to short them. In reality the mortgage market didn't crash until people started defaulting on debt en masse and the vehicles to short the mortgages existed a long time before the market crashed.