Theoretically, could a self propelled howitzer platform be redesigned to use a high velocity 105mm (or whatever caliber) gun which would fire otherwise unpropelled laser guided rounds? It could be made effective up to certain altitudes, say 5-7 km. Granted, the whole price/effectivenes thing is questionable, as to this day we didn't even see that italian 76mm system accepted into proper service anyhwere, even though it's touted as a great ciws/AAA system.
The naval version of that Italian 76 mm gun turned out to be a thoroughly unreliable POS. The USN de-rated it to 90 rounds per minute ( from the advertised 120 rpm ) in a vain attempt to keep the thing together. It is a done deal now, replaced by the Bofors 57 mm gun, which is simply superb. 220 rounds per minute ( ! ), a range of around 15,000 meters and utterly reliable.
Back when navies used guns of 115 mm plus in caliber for anti-aircraft use, there was never any hope of scoring a direct hit on something reliably with a gun of that caliber, nor could the turret rotate fast enough to engage fast movers. These guns were used to put up flak in the path of incoming aircraft. The hope was one or more of these exploding shells, which put a lot of hot shrapnel in the air, would burst close enough to an enemy aircraft to pepper it with shrapnel and damage something. As aircraft speeds increased this became impossible, and you will notice the US Navy abandoned this technique completely. The old 5 inch/54 caliber Mk-42 mount pretended to be an anti-aircraft mount, requiring a 40 rpm rate of fire. To do this the gun had duplicate ammunition loader drums and ammo hoists, making for an achingly heavy 66 ton turret and the need for 11-20 ammo handlers below decks. This is the gun seen on Knox class frigates and Adams class destroyers among others. The current Mk-45 mount has only one loader drum and hoist, limiting the rate of fire to around 16-20 rpm ( 16 if the automatic fuse setter is used ) but at 24 tons this is the lightest 5 inch gun made. Also max elevation was reduced to 65 degrees vs 85 degrees for the Mk-42, eliminating the need for the previous gun's overhead cradle and loading tray. No need if the gun is not shooting at aircraft. The below decks crew is reduced to six. All of these guns can be fired without human intervention until the loader drum is depleted, then you need strong backs to lift shells and powder cases into their respective hoists and then to replenish the carousel for sustained operation. MTBF is rated at 100 hours.