The caliber issue seems to get a lot of play but it is only an aspect of the replacement. Any firearms system replacement for the military is considering the all system aspects and the terminal result of the projectile being launched is often overshadowed by a myriad of other factors. And DoD did recently order even more M9 pistols but as replacements for those that have worn out or do not have the features of the newest mods. Can't forget that even if the M9 is replaced by another model, the military will keep the M9 somewhere in storage as happened to the M1911.
If you would only recognize that life is hard, things would be so much easier for you.
Louis D. Brandeis