This really isn't a one-dimensional question with an easy "studies have shown" answer. For a start, it would require a definition for what "benefits host countries" means -- benefits tax receipts? Proportion willing to volunteer for the army? Benefits eployers of low/high-wage labor? Number of companies founded? Strength of the literary tradition?

That said, the most obvious parallel here is the indians expelled from Uganda [1], who were essentially the merchant class of that country. And I believe have done very well in England.

[1] https://en.wikipedia.org/wiki/Expulsion_of_Asians_from_Ugand

I don't think that's exactly what eggsnbacon1 was saying.

It may be true that all kinds of immigration greatly benefit host countries in the long term, but this is more debatable than that allowing wealthy, liberal, educated immigrants is a net benefit to host countries.

We can argue about the long-term benefits of open borders. I don't believe eggsnbacon1 was stating a position there--more like pointing out that there are some short-term costs that generate popular pushback. But ushering in the cream of the crop is obviously beneficial; it's a no-brainer.

It's country dependant (and study dependant) : https://www.lemonde.fr/societe/article/2020/01/23/un-rapport...

Most studies does not account for what people dislike in immigration : fracturing social contract and communities shattering. Frictions in the salad bowl are poorly translated to economic figures but folks live it everyday.

So look carefully at what each study says and its perimeter.

One should curb down its sureness of that matter.