Thank you for your opinion. Everyone has the right to it.
I think that you take the trade is very simplistic. You don't take into account the option when people buy and sell bitcoins all the time. That is, instead of buying Bitcoin at 100$ and selling at 20,000$, I, for example, bought it for 100$  — sold it at 200$, bought it back at 120$ — sold it at 300$, bought it back at 150$ — sold it at 450$, etc. This is just a primitive example of how, on the road to 20,000$, anyone can earn on the purchase / sale of Bitcoin. All that is needed for this is knowledge and experience. I think you have neither. I don't want to offend you with this, I just want to show you that with knowledge you could look at Bitcoin from different sides and understand that you can constantly earn money on it (like in any other currency). And even if the time comes when Bitcoin goes into non-existence, until then you can earn hundreds of thousands of dollars (or even millions).