History repeats itself. In 2000 I saw the same enthusiasm of young people around how much money they are going to make on the Internet.

The parallel that is important to understand is that Pets.com went bankrupt, but the idea that people would buy their groceries (including pet food) on the internet was correct and very common 20 years later. No one should be surprised if Bitcoin may goes down to 5k. But you should be surprised if no-one is using distributed ledgers 20 years from now.