If we'd just stuck with what worked with the .45 we wouldn't be going through all the wasted time and money looking for a new handgun every few years.
I think far more speculation about service sidearms occurs on the internet than the actual military. The Join Combat Pistol program is long dead, as is its successor the Combat Pistol program. The US military recently bought a large quantity of new Berettas. The M9, or M9A1, isn't going anywhere any time soon. There are a lot more important problems on the table right now.