You seem to assume that just because similar industries exist near each other in China, that it must have been government intervention. Which maybe it was, I don't know. But this same trend exists in the USA too.

You have areas with lots of Oil Refineries, Houston and Baton Rouge for example. You have areas with lots of steel mills, like in North West Indiana. These are examples I personally know of. Obviously a lot of big tech factories exist close to each other in Silicon Valley and in Austin Texas too.

There are "industrial clusters" in America too, simply put. It is natural for large chemical plants or industrial sites to build up near where their source is. Hence all the oil refineries around the gulf. This is not a uniquely China thing at all. Lots of major US cities are known for specific types of industries.