不知道这样的思路可不可以：
1. ignored other factors expensive frame might not be the cause of little profit
2.false assumption assume frames manufactured by the company itself will be the same with outsourced frames. quality/ special style that customer prefers.
3. loss exceeds gain own manufacture line not sophisticated enough to produce enough frames to satisfy current eyeglass production. thus fewer eyeglasses made = less revenue = loss might exceeds save.