I can't tell if you're being sarcastic or not...
If not, then from this, I can assume you'd say the 9mm is underpowered as well. 44 Mag is a lot of gun to carry around for almost everyone, and most people would say a Desert Eagle is overrated. If you're trying to make the point that you'd take a long gun over a handgun in a gunfight, well, I'd agree with you there, but I have trouble concealing my Wincester Model 70, my Mossberg 500, and AR.
I'd say that years of ballistics testing and real world street performance would say you're wrong.
Please tell us what you'd recommend, and give me your ballistics testing and real world street performance data, so we can compare it to the two (or three) most popular calibers you think aren't powerful enough.
All service caliber handguns are underpowered. We don't carry them because they are the most effective tool in a gunfight. We carry them because they are convenient. That is the simple truth of it. None of them are "stoppers". They just don't have that kind of power. This isn't Hollywood and people don't just drop dead because of a handgun round to the torso.
Also, I have heard tons of ridiculous claims about what people think a 45 will do. It is z good round but it is absolutely over rated.
Also, there are lots of factors people overlook. How hot is a round loaded? What length barrel? What bullet? What size/weight gun? Shooter skill? When it comes down to it, what matters is the ability to put shots on target quickly and accurately. A rifle would be great but it does no good when you leave it at home. A 9mm that you shoot well and have with you does a lot more good. For that matter, few people will stand there and let you keep shooting them with a 22. Most handgun "stops" are a result of fear and pain, not incapacitation.
Anyway, to say that a 40 or 45 is obviously enough gun but a 9mm isn't is just foolish. That is what I was responding to and as I have said before, anyone who thinks their service cartridge is a stopper should take it take it to the woods and be humbled.