That is objectively dirt-cheap compared to basically all of the west.
Yes, wages might be even cheaper in neighboring countries, but those lag behind in infrastructure, education, political stability, availability of capital and network effects from existing industry (and are thus not a viable alternative to China yet for lots of things).
I agree that infrastructure, supply chains, political stability, and education are the primary drivers for attracting manufacturing to China.
This is a good point, but I think that only really the underdeveloped/underindustrialized/unstable parts really qualify, possibly Romania, Serbia, Ukraine, with similar caveats than Chinas neighbors.
Despite all this a lot of European manufacturing (e.g. cars), has shifted into the more viable low-wage countries over the last decades (despite language barriers and very high automation; talking mainly Poland, Slovenia, Hungary here).
You still need labor to build, maintain and operate factories, even if they are filled with robots; people here underestimate the benefit of cheap labor by a lot.