AM sold enough chips in less than a month in April to pay for gen 4 but used the money to fund the 60 Ph/s worth of gen 3 chips as gen 4 wasn't ready then. Given the months of chip sales, Tube sales and self-mining since then, AM likely acquired enough funding for gen 4 long ago. They just have to make sure it's free of major problems and get it out the door as soon as possible.