In September 2017 John McAfee in one of the interviews said, that it's worths to his company $ 1000 to mine 1 Bitcoin. From that moment difficulity of the network has rised 3 times and miners revenue got cuted as well. Right now payback period of any mining equipment is already more than 200 days.
Or real cowboys mine even at loss?
I started a conversation on reddit about this subject. You can join it there if you like.