Matthew S. Whiting wrote:

And the profit motive. The latter can exist without competition. The
edge is certainly much sharper with competition as now it is that much
harder to make a profit, but making an even larger profit is still
pretty strong motivation.

I question this reasoning only because regulated markets haven't been shown
as all that efficient, and it's tough to imagine that private ATC would be
unregulated.

In theory, the "right" regulation would promote efficiency. But what's
"right" might not even be known. More, were it known, it still might be
politically "expensive", and therefore forgotten.

However, we should all be aware that there is one bit of "low hanging fruit"
for a private ATC venture from an efficiency perspective: kill smaller GA.
If the "benefit" factor in the efficiency ratio is anything like
"people-miles moved", getting smaller GA out of the ATC system would
improve the benefit/cost ratio.

- Andrew