I believe the idea is more so to grasp at the underlying philosophies behind what is taught as an ideal to, say, infantry leadership, as opposed to merely copying bureaucratic institutions and styles. The US military is a first-rate logistics and fighting force with a lot of hard-won lessons, wisdom that is sometimes even written in blood.

At the end of the day, it's really just a good place to start thinking. You'll find great bits, and parts that are completely irrelevant to a civilian workplace. After all, it's not as if I can smoke my team when they fail to meet a deadline or engage in some "physical correction."

As opposed to most startups, which are tiny, unreliable organizations with a generally substandard management culture?

Bad management is everywhere.

Being able to do even a mediocre job at the scale of a major military is still not entirely unimpressive.

There may be tons of examples of substandard bureaucracy in the military, but that shouldn't detract from the smattering of great leaders within the ranks. Some of the best advice I've ever been given for surviving adult life was advice my father cribbed from officer training in the army.