The miners are more than likely expecting that the future value is worth much more than the electricity today. Bitcoin went from 1k to 20 k inside of a year. If that happens again, or more, they would be able to sell at 10x the electricity cost.
It won’t. It’s a bubble. No real commodity or currency increases 20x in value in a year. It’s funny-money, Just like the dotcom Boom in the late 1990s.
Bitcoin is basically unused as a currency except by criminals, and has no functional advantages over other payment systems for honest people. Just like stock of pets.com in 1998.