Picture this: A massive destroyer receives the location coordinates of an enemy headquarters more than 200 miles away. Instead of launching a million-dollar Tomahawk cruise missile, it points a gun barrel in the direction of the target, diverts electric power from the ship's engine to the gun turret, and launches a 3-foot-long, 40-pound projectile up a set of superconducting rails. The projectile leaves the barrel at hypersonic velocity--Mach 7-plus
woopeee we get the shit shot out of us from 200miles away by an electric rail gun or lasered by a hercules from 20miles away
maybe learning to use the weapons they already got would be better money spent
But the achilles heel of all indirect precision fire systems has not been addressed - you need to tell the projectile where the target is. Very accurately. And if the target is moving update it as necessary.
The equipment necessary to provide accurate real time positions is not cheap or simple - and how would it benefit you in an urban fight where you can't see through buildings ?