If the Army is just going to pick what they want anyway, why do they even do testing?
Pretty much every trial in American history has gone this same route.
The AR-15 wasn't as good as the Stoner 63, The Garand wasn't as good as the Johnson, the tests that led to the Krag didn't even include American manufacturers, and even Colt open-tops fared much poorer than several of the designs they were up against, and the only reason the SAA was such a hit is that the Army basically told Colt it wanted something more like the Remington-style revolver, so Colt built one.
If we talk about vehicles I'm not sure we've made the best choice since WWII (barring, maybe the C-130 which I have rarely heard a complaint about), and the main reason we made good choices then was that we bought whatever we could and pretty much tested everything in the field.
I think the M2 machine gun and the 1911 are the only two arms I can think of that won their respective trials fairly, and even then Browning wasn't happy with the 1911 due to its over-complexity compared with the Savage it was up against.