The US Army recognized long before 1985 that the fleet of 1911's was in poor repair. Most had been arsenal refurbished twice and were then coming to the end of that. I had enlisted back then and was shooting them in the Reserves - there were still items like Union Switch and Railway 1911 a nothing still in the inventory. Those were 72 years old back then. The only other weapon still in service nearly that age were crew served, like the M2 .50 cal.
You can't keep shooting old guns forever - and fixing them up costs more and more as time goes by. It was determined it would be cheaper to upgrade to a "combat" pistol, and the rest of the armed world nations agreed on that definition as being double stack, double action. For all purposes of this discussion, we accepted the M9 Beretta in 9mm.
That was 1985 - 30 years ago. Again, the fleet of M9's is seeing a lot of wear and tear, they won't last 72 years. Weapons, like motor vehicles, last about a 20-25 year service life in the military and then they are replaced or updated. Since there ARE issues with the Beretta it's a good time to include them in a new specification and move on. Plenty of LEO and foreign military users have already shown the benefits and it's the DOD who lags behind adopting them out of a sense of "not invented here," and the obtuse conservatism of shooters who don't like anything until it's been proven in use for at least a decade.
Do we need grips in different sizes, yes. I shot the 1911 and it was fine, moving to the M9 was "meh" at best - large double stack grips in alloy with added panels over them aren't as small as can be made. The gun has an overabundance of safeties on it - per the parent Branch's oversight, the AIR FORCE, who was in charge at the time.
As for the budget, arms procurement is a drop in the bucket. Millions to us, but way less than the amount of oil burned in a few weeks of peacetime duty, much less the "light" bill for electricity. They go thru a formal process so Congress thinks they are punching all the buttons and being careful with money. Like, Congress is good at frugality?
Point being there will likely be a new combat pistol - and so what? It's not a primary combat weapon, it's token of rank for officers and something the MP"s need to establish authority for their presence in peacetime. The real guns are all SIG's in the hands of CID, etc and small operators use what they like anyway. It's really only of importance to those who think sidearms are some kind of magic bullet launcher and important on the battlefield - which, they are not. If you go into combat, be assured, officers take M4's, so do the MP's, and I don't remember Osama getting shot with a pistol, either.
Much ado about something that is basically a badge meant to impress onlookers - pistols in the military are simply showpieces. The last proven combat pistol was the 1911, specifically designed for a reason and used because of it. Which brings up that those which did survive Clinton having tens of thousands milled into scrap might be up for sale thru the DCM in the future. They have little else and will close their doors if they don't get them.
There are just enough for the DCM to sell on a very limited basis for a few years, and then, they will be gone. Don't expect matching numbers or even the correct slide on a frame - again, most went thru two refurbishings and were issued again, surviving Vietnam. Full metal pistols are more expensive and are unnecessary for long term use durability.
Expect a plastic gun with removable grip panels and service provisions for short frames and slides for concealed carry to meet how issue SIG's are used. With the FBI going back to 9mm and having to still toe the NATO line the talk about a different caliber is likely not going to happen because the vendor has to come up with all that in advance with his submittal for the testing phase. That's all the test ammo, the magazines, etc. Most will just ship 9mm as the window is so short.