Biggest reason was greed among people. We wanted to make money, everyone wanted to get rich, we all purchased or earned bitcoin back when it was $3k or $4k and when it reached $20k we got greedy and sold all of our bitcoins, everyone did. So when the new people heard that bitcoin was going to $20k from $4k they started to invest into it however they purchased the bitcoins we sold as the old timers, which meant they needed to find newer and fresher meat to sell to. When the new coming count stopped, the price of bitcoin started to drop as expected because no one found people to sell to at that price.