[ekimekim]

I think the problem here is security checking, and not just because it adds time, but because it adds a highly variable AMOUNT of time.

Queueing theory says that unless you massively overprovision on available security screening stations, there's always going to be a long tail of latency for getting through security. For example, if a burst of people arrive all at once then you could take an hour to get through, whereas if you arrive at just the right moment you might only need 5 minutes.

The second part of the puzzle is that the plane costs a lot to be sitting around while people board. So it's important the plane spend as little time boarding as possible, which means passengers need to all be available to board at the same time.

I don't really see any other solution to these requirements except for passengers to arrive early enough that the worst-case security latency still gets them to their boarding on time, which means a long seemingly-useless wait for the vast majority of passengers who don't get unlucky.

Of course, the real solution to all of this is to discard or streamline the security theater that happens at airports, but that's a political problem, not a technical one.