[Oni]

This gun sounds incredible but with a price tag between $5,000 and $15,000 it doesn't seem so worth it to be militarily used. I don't know the amount of money it takes to train a soldier to be proficient in handling a gun but it's a skill that every soldier would need, unless the military would plan in arming and deploying untrained men.
Also, as BishOpQ said, it doesn't have as much power as a missle, if the military wanted better technology instead of investing money to give these guns to soldiers they could invest money in advancing their more powerful arsenal.
Does that make sense?

SOCOM didn't even want to implement the SCAR-S (~$3000) because of its cost (despite it out-performing current rifles, like M4). They did end up using the SCAR-H for specific units. Meaning cost may be less pertinent, depending on what the rifle is being used for.