> I think this is a stretch, especially now that we have the internet.

We disagree on your first paragraph, agree on the rest.

I'm surprised you can't find something to agree with in the first paragraph. I feel compelled to restate and clarify points I glossed over, to see which one you disagree with:

1. Foreign researchers can communicate with colleagues fairly well over the internet (in real time, even). Physical presence is not required to do academic research, at least in mathematics or CS.

2. Degree mills, fake credentials, paper mills, etc. exist to get names on stuff for a fee. This is used to game the immigration system.

3. Many US degree programs are used as a vector for immigration more than education, and people who immigrate this way usually try to meet the minimum requirements to stay in the US and do little beyond that.

4. Even when it comes to research, most research just isn't that good and doesn't contribute that much to society.

5. Getting jobs in academia is difficult.

6. Immigration lowers wages due to the basic laws of economics.

7. Given the fact that we have mediocre researchers in abundance, such that they can't find work in academia, there is negligible societal benefit to importing mediocre foreign researchers en masse. Additionally, this is devastating to the local labor market.

8. All other things equal (to the extent it is reasonable to determine), a country should try to ensure that native citizens get priority in hiring, rather than importing replacements.

If you disagree with #8, perhaps you should consider who is going to be willing to spill their blood and give up their treasure to defend a country that undermines them at every turn.