>>518712
>better
Cost-effectiveness is key, anon. They have something that's been in service and has been improved for decades, It takes more than a different chassis and minimal advantages to get anything changed.
There's a reason why we went from the 1861 Springfield to the 1873 Trapdoor Springfield and waited all the way to ~1904 before formally adopting a repeating rifle. We're cheap fucks that overpay for anything military-related and stockpile shit we now can never get rid of.
We won't ditch the M4 for some slightly different take on the M4, but we'll slap more shit on the M4 rifles we already have.
>unwilling to pay a few hundred per soldier
>Army
The US Army is the most coddled branch second to the chair force, anon.