Why is China's automobile engine not the world leader and marine diesel engine the world leader?

Marine diesel engines belong to giant engines, and the super-marine ships whose displacement exceeds 10000 tons to 100000 tons or above are basically low-speed engines using heavy oil as fuel. At present, China is a big producer of super ocean-going ships, and of course, the engine market it uses is also in China, which gives China an opportunity for rapid development and ranks first in the world. Of course, the main reason should be that the manufacturing process of this giant engine is basically manual operation, so it is impossible to use a large number of robots and assembly lines, and it is not suitable for high-wage and high-welfare factories in western countries.