This might not be strictly accurate, based on this statement in the article:

Pierre Rochard, head of research at Riot, says it costs roughly $30,000 of electricity to mine one bitcoin and last year Riot mined nearly 7,000 (implying an annual cost of some $200m). And Riot is just getting going. The company is building a second plant in Corsicana, south of Dallas, that will be double the size.

At current price of $54k/bitcoin that comes to $378 million in revenue per year, with $210 million electricity cost. I'm sure they have other expenses though. They don't seem to sell most of the bitcoin they mine, opting to hold it for the future (when it will be worth zero dollars ).