That's an interesting point, but I guess that this is mostly due to the immigration friendly policies the US has. IIRC, I read somewhere in the Economist that t

That's an interesting point, but I guess that this is mostly due to the immigration friendly policies the US has. IIRC, I read somewhere in the Economist that the US is actually the only OECD country that is not going to suffer from a demographic shift. But if those policies would change, or research universities need to cut down their expenses due to budget problems, I'm not sure how long this would last. (IIRC, when Ireland's economy came to a halt, almost all foreign blue collar workers went back to their home countries in no time.)