Large farms tend to have the lowest power cost, plenty of capital to keep their doors open and worst of all, have difficulty selling their farm or equipment. Here in the U.S., mega-miners like RIOT would have to pay depreciation recapture tax if they sell their equipment, on top of the costs of selling in such bulk quantities. It would cost them millions in labor to even pull out the miners and list them for sale. That's why I said last month that if BTC went to $5k, the really big farms would just shut down like an Egyptian tomb until price recovers to a point where revenue pays for power. Worst case, they declare Chapter 11 bankruptcy and some investor swoops in to buy the facility. The miners will always keep mining, thus the difficulty won't collapse like it did in the past (at least for SHA-256).

I feel like we are in October 2018 where price was down 80% from ATH, the network diff just started to fall, but it took until March 2019 for the real selloff of video cards to be complete.