One currently sees lots and lots of Birkenstocks on the streets in New York. All ages, all styles. And I will admit that I just got a pair of the shearling lined Arizonas (so yes, fluffy sandals) for when it gets colder, because Birks are the best shoes for me when I'm walking 40-50 blocks to/from work.
And editing to add, fashion people LOVE No. 6 clogs. (Those I don't get.)