It is great that you guys have been able to maintain S43 for all these decades. Congratulations are in order, especially considering that the thresholds of many privates are now X-ed out. The glib answer I suppose goes to comparative efficiency but studies in analogous situations always fail to support that widespread idea. I have not been an airport manager but a good friend was a manager at KMYL. Via that friendship, I was able to see the many hidden costs associated to maintaining a public airport, some of those costs being substantial.
True, most public airports are subsidized by the FAA. These subsidies are designed to help offset the additional costs of maintaining national strategic security readiness as well as meeting public requirements. I'm guessing that S43 has no defined role with Homeland Security. Among other things, runway construction and weight capacity is likely far in excess of what you guys have constructed at S43. I was blown away by the complexity of the runway substrate and drainage requirements for the KMYL runway rebuild a few years ago. A few years back, the taxiway had to be moved to conform to revised standards based on 30 years of accident analysis. Finally, there is the question of comparative all-in costs of hangaring or tie-down parking at S43, and how those monies flow. In the end, I think we're attempting to make an apples to oranges comparison. Not fruitful (no pun intended
)