If you go back to say the 1960's and before, college town areas, particularly those in Yankee white and Scandinavian areas would most certainly be Republican because of the wealth gap of those who attended college versus those who don't. Beginning in the 1960's with a diversification of professions in the elite sectors and also with the generational dynamics at play, is when these areas shifted heavily to the left and heavily towards the Democrats. The same thing happened in places like Ithaca and Ann Arbor.
This actually makes Dane County's political history even more noteworthy, because while Tompkins County and Washtenaw County didn't vote Democratic during the 20th century before 1964 other than in 1912, Dane County started its Democratic streak in 1932 with FDR and was only briefly interrupted by narrow wins by Eisenhower in '52 and '56.