Just think back to when the whole ETH rally started in the summer. Bitcoin was what, around 1400 on May 1st. Lets look at just the rally itself. If you bought BTC on May 1st and held til mid June, you would have made 127% on your money. If you had bought ETH, you would have made 760% by mid June.

Now, lets go back to May 1st. On this very day, on Bitfinex, ETHBTC is shorted to 0.0098 in a flash crash at 3 PM UTC, at a low price of 0.0098 btc per Eth. If you were to have accumulated those orders at the bottom of that candle, you would have been able to ride the rally in ETHBTC for a 1464% gain in BTC. Even someone who didnt get flash crash prices would be able to ride a 200% gain buying on the next daily candle.

Lets look where the big play happens. Some clever fellow shorts the shit out of ETHBTC in particular, using BTC as collateral. Whoever gets in on this play accumulates quite a line in ETH. They sell the ETH in June, which sees a drawdown over the next month to 30% of its 400ish top by mid July. BTC also has a drawdown, but only to 61% of its top. 61% of 1464% is still 893%. 61% of the aforementioned 200% is still 122% up. Lets look at what that means for the holder of bitcoin who got in on this play. The worst case scenario is that they more than doubled their money after the drawdown. Their overall cost basis for the bitcoin they purchased is less than half of what it used to be. The risk/reward for staking this quantity of money on margin is now too good to pass up, because they have doubled their collateral. And that's someone who converted straight back to BTC. What about the person who went to fiat and had no drawdown, and accumulated a line of BTC throughout the bear market?

Knowing this, is it any surprise that we had seen such a huge rally of BTC by the end of the year? Follow the money. These cycles have everything to do with accumulation and distribution of positions by people with huge accounts that can move markets. Nothing is different now than it ever has been other than the volumes of money pouring in.