Regional norms should be ignored whenever they are bad. This is Styleforum. Dare to be better!
But of course you're right. Sweeping generalisations are just good for stimulating the discussion sometimes.
I'm sure you're right, and I have walked on Wall Street at least. But I still don't think slippers with a business suit are proper CBD. The Ivy League context with a blazer and khakis, that makes a lot more sartorial sense to me.