Yes but it's a double-edged sword. Draining these talents is a pro for China in the sense that they deplete the pool for America and the EU, our competitors, but really only accept a small cream of the crop because we really don't need a large foreign diaspora in China nor do we want them to take jobs that we have actual local alternatives for, shooting up our youth unemployment. Just take the few we actually need without going so hard to spite others that we inflict serious self-injury with this blade. Self-preservation always before aggression.
kind of a response to you, but also some random thoughts.
While I do think China can have a lot of control over who/how many to let in, making a decision on who/how many is much harder. Running a country means dealing with many factors with complex interactions with each other, and it's hard to predict the exact outcomes. I think we will need to rely a bit on faith and value judgment.
Both Elon Musk and Jensen Huang's parents are immigrants would have fit only the k-visa but not the R-visa. But they created companies that gave the US an enduring edge over China. The US let in a lot of people to have these two to change the world.
From our side, can a Chinese person do the work that Katherine (Katherine's journey to the east, BS from the US, and MS from China) was employed for? Certainly! But I think she has made and continues to make tremendous contributions to China (likely more than anyone on this forum!).
I can think of two reasons immigrants tend to be more successful, given the same degree and even GPA. 1) Self-selection on risk-taking and 2) being bi-cultural from immigration.
I think we can all agree that a degree is not a good predictor of how much a k-visa candidate will benefit China. It's also hard to measure some of the benefits of having foreign workers on the Chinese society in general. I think using rigid measures of GDP and birth rate in the past was a lesson that we shouldn't repeat. The only suggestion I can come up with here is using an interview process that doesn't give an immediate answer and having multiple interviewers to reduce bias (like a job interview).
A crossing the river by feeling the stone approach is probably the right approach again on this issue. Start small and expand over time as we see fit. It will take a while for all the parties (visa applicants, the Gov, employers, and the Chinese people) to iron it out. I don't think people on this forum have fundamental disagreements, mostly just on where the threshold should be.
Also, there is the issue of Permanent Residency, which currently has sky-high merit requirements. I have no doubt China would want to keep some of the k holders even if they don't meet that requirement. It will be a thorny issue as well.