Anthropic is kind of positioning themselves as the "we want the cream of the crop" company (Dario himself said as much in his Davos interviews), and what I could understand was that they would a) prefer to pick people they already knew b) didn't really care about recruiting outside the US.

Maybe I read that wrong, but I suspect they are self-selecting themselves out of some pretty large talent pools, AI or not. But that application note is completely consistent with what they espouse as their core values.