I totally get that there are a thousand critical tasks these warriors have to master in addition to pistol shooting.
When I referenced the million rounds of .45 in a year I failed to note that figure dates back many years when there were not nearly as many operators as today.
I friend of mine in NC shoots with some active duty Army NCO's. He's seen their log book where their team was closing in on 30K rounds of 9mm (through Glocks interestingly) for that month. A friend of mine who is former active Army SF but now a Nat.Guard Grp with multiple GWOT deployments, has related how his half strength team went through thousands of rounds of 9mm in a weekend drill; a National Guard unit. And to watch him shoot, yeah, that made sense as he was strong.
I just think a lot of these guys shoot a lot more pistol than one might suppose. And this volume and the pistol maintenance required or not required is probably a factor in their choice of guns.