Start checking the list, the M14 didn't win any wars, either. Wars are one by soldiers, not the tool. Compared to the AR15, the Krag Jorgensen is less than adequate.
Military has been working on replacing it for ages.
Look at that from the other side - instead of being a jammomatic that haunts the military stuck with it, the design is so adaptable that updates over the last 45 years continue to prove it's superiority. Nothing else so far has been able to justify replacing it - not even the SCAR in SOCOM use. "No real difference" is how the commanders of elite force put it, and they should know, they only get command by having been there, done that.
In the military, it's not the "Unknown Boss" who can't actually do the grunt work - they did, did it well, and aren't too good to do it again. I've been served by General's in the chow line, they are there to prove they can lead by doing, not by position. So if the command of SOCOM says the M4 gets the job done, it's because they've used it, it works, and there's no huge change in tactics that yet makes it obsolete.
Apply those attributes to civilian use, just the same as we have with most of our other firearms, and you find it's an obviously superior design that gets tough work done. Unlike a tightly fitted, exposed action curio firearm still in production, military arms are more user friendly, easier to clean, have a tested and reliable operation, cheaper ammunition, and have numerous sources of parts available.
There's over 20 million prior service men and women trained on it, who can disassemble it in the dark, put it together, and shoot it accurately. Can you do that with a lever gun or even a Mauser?
With over 9 million made in the last 45 years, over 65 countries equipped with it, and the AK going out of service in major nations, yes, the AR is the gun of the age, and will continue to be for the forseeable future.
We haven't invented anything else any better, and what few changes we make are only one small part of the overall design. The competition copies most of what it does, because it's become the standard to work from, not ignore.
For those who want to remain less than knowledgeable about that, it's a free country. Go right ahead. You do so being protected by it, tho. Remarkably ironic, isn't it?