The end game probably involves < $1000 autonomous drones that target IR or RF and drop something like hand grenades. On the defense side, there would similarly-priced interceptors with bolas, backed up with sharp-shooters for important targets.
At that point, it turns into a logistics problem that's much easier for the attacker than the defender. Iran's already demonstrated that one successful drone can do $100B-1T in damages, so a hit rate of 0.1% means a 1:100K cost:damage ratio.
