Considering that .38 Long Colt was even weaker than .380 ACP which many folks consider to be the bare minimum for civilian self-defense, I'm going to be bold here and side with the U.S. Army on their decision to upgrade to a more powerful cartridge.
Furthermore, I'm going to be even bolder by making the statement that I think that the U.S. Army was a little more informed regarding the threat and what it took to deal with them than anyone here.
I've seen the argument made many times before that .45LC and later .45 ACP didn't solve the problem and was no more effective than .38LC, but seeing as the U.S. Army stuck with .45 up until a century later, I presume that it must have been, otherwise they probably would have gone back to .38LC or otherwise opted for something even more potent than .45LC in order to address its inability to deal with the threat of the Moro warriors.
I honestly think that too many folks rally behind their cartridge/caliber of choice too much, often to the point of trying to push it as the end all, be all, and denigrating everything else.
Obviously, I'm a fan of .40 S&W, but I'm well aware that it has it's own distinct disadvantages and is evidently not the optimal choice for everyone, so you won't see me trying to push it as such, much less will you ever see me making ridiculous statements like that anything more powerful doesn't need to exist because to heck with the laws of physics, they don't fit my agenda.
In fact, I've often chuckled when I see various firearms/ammo manufacturers who market it as; "The Powerful .40 S&W!" because in my opinion, compared to magnum cartridges, (much less rifles/shotguns) it's not. Heck, it only has like 50ft-lbs of energy over 9mm, so it's not even substantially more powerful than other duty cartridges.
Yes, I still love it. Yes, I still carry it. Yes, I still trust it. Not because it's the illusive one-size-fits-all cartridge, but because it works for me. That's all.
I don't understand why more folks can't be like that. Why is it so important that one's cartridge of choice be the best? Why can't others be better, even if only in particular roles? Why can't it potentially be better in the hands of another? Not that I expect a tangible answer or anything, I'm merely attempting to point out the flaws of such unilateral thinking, perhaps even provoke some actual thought on the subject, reflection on such sentiments and what deeper meaning they may possess on an individual level.
Regardless, this thread was never intended as a platform for folks to push their cartridge of choice, and certainly not a platform to denigrate the choices of others, so I would appreciate it if folks would refrain from doing so, or at least refrain from replying to others who cannot resist the urge to do so.