Even after the recent Hukou reforms, permanent residency for immigrants is nonexistant (less than 20k in the past 2 decades). It feels like such a huge own-goal in the current historical moment to miss out on attracting migrants, especially the now unemployed technical experts and scientists in deindustrializing nations. Have they perhaps been infuenced by the current wave of fascist hysteria in the G7? (By which I mean: the CPC proactively stopping such a movement from forming in China?) Are they high on their own supply about being a "civilizational state"? Are they scared? Are they CHUDS?

Edit: It genuinely doesn't make economic sense at this point. For example, West Europe would honestly be a sterile crater at this point without immigrants from the past 20 years due to population decline.

The best reason I could come up with is that they fear backlash from the precariously employed youths and xenophobic elders.

Edit: Historical inertia is probably a large factor here. It would be somewhat strange to switch from population control to population bolstering policies in under 2 decades.

Edit 2: Vietnam is somewhat similar to China in governance, but is more leinient with immigration than even Europe.