You need 243 gold per minute for 1 day to 198 for 7 day of autominer for it to return its cost. Simply saying for now there is no player for whom it would be worth buying as of cost/efficiency ratio is too high.
I do think you misunderstand the reason why there is even an autominer :p
MyBitMine explained earlier that the autominer isn't and was never really ment to make profit on, it's a away for early member to have a way to earn every min for x days

If I would compare my income to the one I would need to make a profit I'm about 10% of the way to make it break even, but still than, the autominer, costing me more than it profits me, helps me allot

I can mine a average of 1.5 upto 2 times more a day, I'm upgrading way faster
