Essentially, large players are using the market to hedge their underlying spot position.
As long as there is a contango ( price trades at a premium to spot), there's a valid hedge opportunity on any price drop.
This means that if a large player is long a future at $18k and long the spot market at $17k, there's a traded premium per contract of $1000.
If the price falls then to $10k in the spot market, it's likely that the premium will remain. If both positions are then closed out, you net the (premium * amount of contracts bought) - the underlying spot position.
It's likely that with the availability if hedging in this nature, whales have ground down the market to shake weak hands out - they've built up tension where smaller traders do not know whether to hold or get rid, and the weak hands have jumped out.
The whales have not really lost any money since they have the hedge, but can now buy back at a 50% discount vs the start of the year.
This Friday, I'm expecting a bounce across all coins since most coins are tied to the BTC price move.