Dear Mr. Rawles,
With respect to the great sidearm debate, I suspect that a much underrated feature of the M1911 family lies in the ubiquity of the family. As a disclaimer, I should note that I am an unabashed, though not uncritical, fan of the 1911 design.
I am much inclined to believe that the Schumer and the fan will become commingled in my lifetime. Assuming that they do, the ballistic superiority of a round may become less relevant than the availability of spare parts, ammunition, and expertise for keeping the gun functioning. When you start to think of these factors, the superiority of the M1911 proclaims itself.
With respect to the availability of ammunition, I believe that the .45 ACP and the [9mm] parabellum are equivalent. This factor, however, militates against the use of flavor-of-the-month (though possibly ballistically superior) rounds such as 10MM, .357 Sig, and .40 [S&W]. My father has frequently said that you can't depend on a weapon for which you can't find ammo in the boonies of East Texas. When you get to that point, you are left with only two real choices in pistol calibers.
The availability of spare parts distinguishes the M1911 from all comers. The CONUS "installed base" for 1911s is in the millions. I am given to understand that a total of 20 manufacturers currently produce M1911s. Because of this breadth of install base, the local gunsmith keeps enough parts in stock to perform any repairs that I need. Even if his stock runs dry, there are M1911s salted away in places that you never expect, all of which may be cannibalized to provide my 1911 with some part or another in a pinch. There is a great deal to be said for the fact that my next-door-neighbor has one, one of my coworkers has one, another coworker has 3, my financial advisor has one, all of the guys that sell guns to me carry them for self defense, my best friend from college carries one, my best friend from grad school carries one, and his roommate keeps one. Ubiquity means that somebody probably has a spare recoil spring. If the Schumer and the fan become commingled, I may need that spring. I bought a 1911 for cash once because I knew that, even if it didn't fire, the parts were worth more than I was paying.
Let us now talk about expertise. Again, there are more people in the world who have had to disassemble and diagnose a 1911 than have had to perform these operations on a Glock. If my 1911 becomes unhappy, that base of knowledge may be incredibly valuable to me. I have addressed a pragmatic set of concerns for logistically grim world. I don't carry 1911s because of these grim concerns, but I do think that they should legitimately inform the discussion among your readers. My best regards and a Merry Christmas, - K.A.D.