Comment by bodzioney

Yes exactly. Aarhus had Martin-Löf, Nygaard, etc. Similarly, INRIA has had many influential researchers as well as OCaml and Rocq. Talent (and exciting projects) attracts more talent. But that doesn’t mean it doesn’t exist in US. Penn, Cornell, CMU, MIT and others have had historically very strong PL faculty. My understanding is due to the nature of grants in US it doesn’t give faculty the same freedom to work on what they choose as in Europe. So you get different research focuses because of that.