The massive proliferation of battlefield SAMs that are radar-guided as eliminated the rationale for the gun, which was used to attack before SAMs could engage, as most SAMs in the 60s were IR only and had to attack aircraft after they'd already passed. Engaging at altitude eliminates entire classes of battlefield SAMs which cannot engage targets above 40,000 feet effectively, particularly with a cruising speed of 400 knots instead of the 300 of an A-10.
I know the Army doesn't like to be left out to dry, but the SDB is the ideal solution for tank-plinking in the modern day. The reality is, going low enough to engage with guns is just not safe for airplanes when everyone and their brother has very advanced MANPADs and light battlefield SAM systems which can engage head-on and cross-angle. The Air Force isn't going to divert the Scorpion to fight air to air or do penetration, because it's bad at those things. So it is what the Army could count on for the 21st century.
Replace the A-10 fleet with 400 of them in the ANG. The expansion of capability that represents for a host of missions would be substantial, and they'd cost less to maintain.
I dont think you understand the capabilities of the SAMs our peers are using.
There are at LEAST 3 SAM classes that can easily engage any aircragt at altitude.
I know I had to look this up on WEG for an exercise.
There are plenty of SAMs out there that can reach even the U2 at its max height. The SA-2 and SA-5 are examples of this.
Also, tanks arnt everything. One can make it easier to stop a tank without destroying it then one can infantry. Which is why SDB are not as good. Infsntry still wins wars, and having an infantry killer in the A-10 is where it is at.
The A-10 can also kill tanks from above, especially since engine decks are not heavily armored. It's rounds can easily penetrate the sode of it.
Also most MANPADs have a lock on time and the person using it would have to be having it ready if they would want to attempt to hit the A-10 when it is flying as low as it can.
Also, light battlefield SAMs are a threat to again, anhthing not flying at its lowest
They are not made for something skimming tje trees to attack it.
My job is knowing this stuff. I know it well.
Any AAA would be useless as it would not have the stopping power to down an A-10.
Basically by what you are saying we should us either Scorpion because it can kill tanks better...but what about the infantry? The lighter armored stuff? Why waste SDB when bigger ones would work better? Or better yet. A gun.
Think of it in terms of the Army and what we would be using it for. As in calling it in for.
Why do we want SDB for spread out infantry and risk losing air support when we need it because it has to rearm?
There are benefits to both of them.
But the A-10 is the better CAS vehicle. The Scorpion is a great light bomber. Not good for what rhe Army would be using it for without it having to carry more then just SDB for vehicles...