you do release the world is much bigger than the U.S right? i pay less than 2 cents per kwh , and 0 tax on asics.  so my profit and ROI are pretty much different from yours , nobody pays 24% for miners except in the states " non that i am aware of". huge farms in china ship their miners in trucks  " next door to bitmain warehouse" it costs them NOTHING to ship and pay no tarrif + they get good discounts on bulk orders !! and they get cheaper power rate than yours.

and ya people still run S7 but can you with 5.5 cents ? not likely !

what i am trying to tell you is (every one has his own inputs of doing the math), it may work for some while not work for others !

I will not buy any of those asics nor any other asics even with the dirt cheap kwh i have. but it's a matter of couple weeks till you see thousands of them being shipped across the globe mostly to noobs that  will never ROI