One guy here said his profits already paid for his equipment and he does not pay for electricity because he gets it from a green energy source. He can mine for nothing until his energy generating equipment or mining hardware breaks. No doubt he's in a minority but there must be others like him.
Yup, I'm like him. Except my electricity isn't from a green source. It's free, included in my rent. So I'll never stop mining. As for everyone else? I don't know what their excuse is...