Y'all ain't looking at this from a Pentagon point of view.
The problem to be solved is, how to you retire fat, rich and happy? You don't do it on a Pentagon salary. You do it on a defense contractor consulting salary. And those you get by buddying up with a defense contractor who's got a new platform that's maybe better, maybe not, getting it adopted, retiring from the pentagon, and getting hired by that contractor into a nice, cushy defense contractor consulting job.
For those guys, it's got nothing to do with whether or not the caliber is better or not. Although if they can convince themselves that the new platform has advantages, they can use that to veneer their soul they don't have to look at their own lack of moral fiber.
Now, add to that that 223 needs a particular twist rate and velocity to do well, and it becomes a really interesting discussion, doesn't it?