Die size is 640mm2, die cost is ~$42(asumming TSMC's yields, chinese fabs have much lower yields) - so at volume manufacturing cost(including test and package)

Die size is 640mm2, die cost is ~$42(asumming TSMC's yields, chinese fabs have much lower yields) - so at volume manufacturing cost(including test and package) is surely less than $100 ,closer to $60-70. And in large enough volume, assuming 50% gross margins, sure it could be cheaper.