This is possible becasue this time all the market is down and so many peoples will just invest their money now and they hold all their coins and they sell their coins when the market go high and they make good profit in the market.
If you buy at the dip, I think It's possible to double investment from bitcoin.
Of course , you should hold for several years again.
You sell when the bullish season, It might happen at 2023 or 2024.
Bitcoin will touch around 75-80K USD at 2023.
Many investors also predicted bitcoin will reach around 100K USD at 2024.
I agree with this prediction.