Sustained rate of fire isn't as important as you've implied. First off, you'll either burn out your barrel, or run out of ammo. Two, most fire missions in high

Sustained rate of fire isn't as important as you've implied. First off, you'll either burn out your barrel, or run out of ammo. Two, most fire missions in high intensity combat will be shoot and scoot, where each system fires 2-3 rounds then moves to a secondary fire position to avoid counterbattery fires. In low intensity combat situations where relocation isn't a requirement (Iraq/Afghan), firing rate is completely unimportant. And you're also ignoring ATACMS. HIMARS is nice for the Marines, but ATACMS is great for high intensity warfare. And the SU-25? Junk. It wouldn't survive 30 minutes against anyone with a decent AD (though neither would the A-10). Everyone underestimates how lethal modern combat will be against any and all aircraft.