i can argue they ar enot even selling 50%, since they don't need that much to cover their bills
Are you sure about this?
If you buy some hardware today, you spend money and that hardware is obsolete in less than one year.
Then there's electricity.
I'm not so sure they are earning so much.
yeah i'm sure they are earning like 4 times what they are consuming, so at best 25% goes in the bill, and that only with the recent diff increase, 1 month ago was six times, and before that was even higher 8 times or more
Strange, because ANY calculator I used showed me that after having spent money for hardware and electricity, after the first 3-4 months I pay back the costs, and what remains from that moment on is not much really, and after 6-7 months you better turn off your old hardware because difficulty has grown so much that it becomes counter-economic.