last couple of weeks bitcoin price dropping down too fast.Many crypto investors are getting worried for this reason.
You didn't include enough options IMO. The real reason is because this insanely high price wasn't even close to warranted in the first place. There are gov crackdowns going on, private company crackdowns, alt coin competition, transaction/scalability issues, etc... I won't be the least bit surprised if bitcoin's value is $0 in a few years. This bitcoin price hit is different from all others in the past, and I've been following this since mid 2013.
If 20k was not realistic zero is even more unrealistic, do you think that with all that is behind bitcoin, like the miners, the devs and the community the price can reach zero in a few years? Sorry to disappoint you but it is not going to happen, the current price is closer to the real value of bitcoin but as we know this can change due to external influences and that is something we will have to accept for a long time.