[qball]

>something which 9mm doesn't do reliably

Neither does .45, of course. Handguns (well, 9mm anyway) dispense what is functionally a single pellet of buckshot- the pellets (while still potentially lethal) aren't that powerful on their own, which is why the shotgun launches 8 of them at a time.

>but there are draw techniques which rack the slide and the gun is designed to enable these

The 1911 was designed back when pistol doctrine was "carry with chamber empty" and "fire one-handed", despite that not being particularly conducive to accuracy. Pistols are a badge of rank more than anything else; the overwhelming majority of military casualties caused by them are same-side (used on deserters, etc.).

>small magazine compared to 9mm

Not really. Remember that until the '80s, the concept of a "double-stack" handgun was limited to the Hi-Power; every other 9mm handgun had a capacity of 7-8 rounds, just like the 1911. And now you know why revolvers lasted so long in service- because not only were you not giving up capacity in those days, but you had a consistent and safe (though heavy) trigger pull, and you could use hollow-point ammunition without risk of a jam (which 1911s are just flat out unreliable with).