As China's Auto Production Capability Has Evolved, It Is Unclear

As China's auto production capability has evolved, it is unclear whether protection was beneficial or harmful. Why?

A) Accounting data must be translated from Chinese to English, and that is a difficult task.
B) After 30 years of infant industry protection, the tariff on auto imports is still significant (a 25% tariff) .
C) China will probably never achieve exports, so whether any gains were made is unclear.
D) Chinese consumers are exerting more market power, and they are opposed to any kind of import protection.