Perhaps specialties in large urban govt bureacracies (like GIS, facilities maintenance, etc.) often require many Windows-only apps and drivers from vendors whom

Perhaps specialties in large urban govt bureacracies (like GIS, facilities maintenance, etc.) often require many Windows-only apps and drivers from vendors whom can't justify Linux development (Mac would probably be first). Having IT supported a similar type heterogenous mix of departments in big name Ivy academia, it's typically workable productivity/interop to have each group of users to standardize on the same OS... usually either Window or Mac but not both (because of app compatibility, even between same vendor isn't always 100%: filename character set, fonts, so on.)