The whales - and anyone else with half a financial brain - are slowly selling all their bitcoin. As they sell, prices begin to drop sharply. They then hold back on the selling and newbies and "HODL'ers" are foolish enough to "buy the dip". This sends the price back up.
It then repeats with rates dropping again, until the newbies and "HODL'ers" buy the dip once more.
Except on every round the dip gets deeper and deeper.
The game is over, and anyone so stupendously stupid to keep buying from the whales who are unloading are basically just throwing their money away.
Face up to reality, the party is over.
Many short term investments are being made during the drops of the prices and ends when it peaks. And it usually peaks during holiday season. But it is not very certain if the profit you will earn is enough for those months you wait. There's still some who extended their period of investment to another year because bitcoin still grows in annual basis.