Apparently that's going to be a lot harder as the Party starts looking a lot closer at foreign work visas over the next few years.
Those who are not educated from East Asia can't easily come to the US illegally as those who can cross overland (Mexico and central America) can. Poor Chinese villagers are not boating to America.
First, much of East Asia has extremely demanding placement tests for elite high schools (and sometimes lower schools). You might reasonably say that we're only taking students from good high schools around the world, but that's a comment about school quality, not students. As people often point out, Harvard dropouts are almost as successful as Harvard grads - merely getting in represents a powerful filter. So it's plausible that we're taking rich/educated elites worldwide, but in East Asia we've got a talent/skill filter comparable to college admissions being applied in advance.
Second, your point: there's a non-trivial penalty for being a Chinese applicant to a US college, and it's not particularly obvious what impact that has. I suppose it could be that the harsher requirements for acceptance are driving the difference, and we don't have any real evidence on how responsive outcomes are to changing that restriction. (Is there a good breakdown of outcomes for a given group by visa type? That might show whether nation-specific admission rules on some visa types are changing outcomes.)
(The third thought, of course, is "it's a huge multifactorial mess and there's probably not enough data to trust any conclusion we come to".)
Second: The non-trivial penalty came AFTER Chinese people became over-represented.
It's not as complicated as you're trying to make it out to be. Something is causing East Asians to outperform us in basically every positive trait. They have higher IQs, higher incomes, lower criminality rates, lower poverty rates, etc. And these stats hold true even generations after immigration. Maybe it feels complicated because you're concerned about the root cause analysis. I'm not. They're doing great, we should want great people here.
(I agree that if the penalty came after better outcomes, it's not a relevant factor. I wasn't familiar enough with which restrictions were in place when to say.)
But yes: the complicated part is root causes, and that's not relevant to whether we should expand our visa/citizenship program; we certainly should. If someone in the thread disagrees with you there, it's not me.
He’s back in the UK now, last summer several of his ex pat friends and colleagues were busted by investigators parachuted in from Beijing. They were detained, their visas were revoked and given a week to get out of the country. Fortunately he was in Beijing when it happened and got Chinese colleagues to clear out his stuff and any paperwork from the college, but he had to roll up all his gigs.