^China is a tax free country for income group $520 to $745
Please use after tax income to calculate.
In China $745 is the take home income and zero taxation.
whether workers are taxed on their take-home income doesn't change the initial cost of labor to manufacturers.
even if we do account for this: the standard deduction is $12200 for individuals in the USA. that means the first $12200 is not taxable.
based on your numbers, for typical chinese manufacturing laborers, the first 115 hours are not taxed. for typical american manufacturing laborers, the first 750 hours are not taxed. without researching the actual tax rates (they both have progressive income taxes topping out at 45% and 37% respectively) that implies american workers are paid even higher when considering take-home pay.
In China, big business rich people pay the most in tax while poor people pay zero tax.
it all comes down to profitability. china has big corporate tax loopholes just like the USA. if it wasn't profitable to manufacture there then businesses would leave. it's that simple.