1) Assembly and repair are completely different tasks.
2) You're paying for repair in different country with different wages.
3) Economies of scale. How many identical phones with identical problems are you bringing in to be repaired using identical steps? One million or just one?
You provide some reasonable explanation, but that still overlooked the value for China's manufacture provided. For the folks of supporting Made in USA, do you think they would accept the price tag that assembly whole iPhone would just charge less than $10?
2) You're paying for repair in different country with different wages.
3) Economies of scale. How many identical phones with identical problems are you bringing in to be repaired using identical steps? One million or just one?