Imagine having one bitcoin.
You sell that bitcoin at the current price(around 3800 USD).
Bitcoin crashes again somewhere around Christmass and the price goes down to 1K USD.
You buy 3.8 bitcoins with the dollars you got from the previous sale and you HODL.
In 2019-2020 bitcoin recovers to 10K USD (or maybe reaches 20K ATH).
You have made atleast 38K USD.

I know it's not guaranteed to happen,but hey,this is the Speculation forum,so why not speculate about this.
I think that this is every crypto whale's trading plan for the next 2 years.
Alternatively, you have 1 btc, you sell now and the price goes to 6k by Christmas. You don't buy back and cut your losses because you think the price will dip again. The price then continues to increase and goes to the previous ATH or higher. You've lost out on 17k+.
There are two sides to this argument always and it's easy to neglect that. As for bitcoin going to 1k it's very unlikely to happen, there are too many strong support levels between the current price and 1k. If it did go to 1k it would probably signal that bitcoin was going to strugge and the price would fall further without some intervention.