I am 65 and a Viet Nam vet.
Personally (for what it's worth) I think that as long as the military is limited to ball ammo that there will still be a role for the .45 ACP.
I totally agree. The rifle is the primary weapon and the handgun is the last ditch alternative if the rifle is out of service, for whatever reason, and the handgun is a means to stay alive until another rifle and/or ammo is attained.
Most grunts did not carry a handgun.
Is a .45 ACP viable? Absolutely. If anyone thinks that a wonder-nine can do better is in denial only because of more rounds. One needs to hit the target in a vital area.
All this talk about the how newer bullet designs for the 9mm have allowed that caliber to "approach" the .45 ACP is just looking at spec sheets. Maybe the cops have good 9mm ammo, but the military not so much.
I have owned pistols in 9mm (2), .38 Super (1), and .45 ACP (3) in my life and now own only one 1911 .45 ACP with good HP rounds, but I doubt that I will be facing any body armor if and when I pull the trigger for a home invasion.
They were Colt (Government and Commander), AMT Hardballer, Para-Ord, and Star PD pistols. Only the Para was a double-stack mag aluminum frame and I got rid of it.
To be truthful, my 1911 is the AMT Hardballer with a lot of modifications thanks to Jerry Kuhnhausen's book. I have had it since 1992 and it is not a factory pistol anymore. I have about $300 total in it, but that was a long time ago. It ain't pretty. It has been my HD/CC/SD/truck gun since then and its runs with anything it is fed with its correctly throated barrel.
And to all of you 9mm new ammo/bullet fanciers, it is loaded with Federal 230 grain Hydrashoks. It will outdo your 9mm loads.
Can't say the same about the other 1911 pistols I have owned.
I am not a big guy (5'-8" and 165#) and the recoil is not a problem. The .45 is more of a big "push" rather than the sharp recoil that many experience with the lighter 9mm and .40 S&W pistols, I have shot both, and don't care for either.
The military and police bean counters have decided to go with the 9mm insofar as cost. I'll bet they never shot them.
Jim