Some of it may also be neighborhoods where solar contractors went door to door selling the systems. Even if you don't buy from that salesman you get the numbers in your head and start to realize it isn't some exotic tech for elite weirdos.

My sister was just such a representative going door to door in Connecticut. This was likely a factor. The southern coast of Connecticut, being in the shadow of New York and thus dense with rich exurban homeowners, is a prime market for such contractors.