It used to be that there was always a supervising controller on duty, who kind of rotated around each active controller, acted as backup for breaks, etc. for this class of airport - from my layman reading at least. This still seems to be the paper requirement.

So the minimum here would be 3 controllers given that nights setup. One for approach/ground, one for departure. Obviously you can argue more would be appropriate to segregate duties further, but it was a night shift headed into airport shutdown.

There seems to have been two working. The supervising controller double booked as a primary controller for departure at the time of incident. The fact the incident controller wasn’t immediately relieved of duty and had to spend 30 minutes shutting the airport down himself seems to match this explanation.

From what I’ve read on the matter for this tower not having a supervising controller was rather normalized - which is outside of SOP and something you need to report to management every time it happens. For this incident there was one - but sounds like one in name only. Once normalization of deviance happens, working in a way where two controllers that on paper should be sharing duties - but in practice are splitting them - seems exactly how I’d expect things to go.

But this is all speculation at this point of course. NTSB report will be interesting.

Either way - it has been clear for decades ATC needs both a massive surge in the staffing pipeline as well as a legitimate modernization program competently implemented. It’s certainly not a problem that started or remained in any single administration. Even if one or another had been worse, others sure as hell haven’t done much at all to fix the situation.

Many airports have intersecting runways to account for changing wind directions.

Are you talking about a two strip airfield on a cattle station in the Northern Territory with once a month traffic, or something else?

Your "gotcha" class question isn't especially well formed.