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Well....that is true for the cost of the center building. It isn't
necessarily true where an approach control serves what is
primarily a general aviation airport.


What's a primarily general aviation airport? One where the majority of the
traffic is general aviation? Yup, there are plenty of airports with
approach control facilities that have more general aviation traffic than air
carrier traffic, but there aren't very many that would have approach control
facilities if the airlines weren't there.



And, it certainly isn't true for instrument approach procedures
established for airports that have no commercial traffic (which is
many, many more instrument approach procedures than those
established for airports with mostly, or some, commercial
operations.


Yup. But a lot of those airports that have no commercial traffic today are
airports that formerly had commercial traffic and exist only because they
were built for the purpose of commercial traffic.