Of course though - this thread is about Windows Server, not desktop - where this should be MUCH less of an issue with properly designed code.
Same code, they don't make it twice. Less hardware hotplugging, but probably just as many lines of code in use.
Less desktop apps on the platform, but you're right - the base code is the same.
Fewer desktop apps, maybe. But in the Windows world, server often is treated as a desktop (like 90% of the time) so the reduction is rarely what you'd hope. And there tends to be lots of server-only code too, often running as desktop apps.