DARPA was based in Virginia... so not sure what SV history you are referring to.
Yes Guangdong is the technology zone for China, it receives both state funding, state run incubators and special economic status.
But in essence they have both highly skilled hardware engineers and software engineers which is like SV of old. Where as current day SV is dominated by software, where they ship the manufacture of things to Shenzhen or Taiwan.
As far as universities, you have Sun Yat Sen University in GZ one of the top tier universities in China. And yes a whole lot of internal migration from the north to the south. Shenzhen growing from 70k to 10mil in 40 years is an insane population movement