What's your point? We already have that. Large bombers are used to deliver cruise missiles close enough to the target area. Cruise missiles are drones by another name. But they're hardly cheap. In fact they're getting more expensive.
There have been proposals to build conventionally armed ballistic missiles to fulfill the prompt global strike mission. The problem is that if Russia / China / North Korea detect a ballistic missile headed in their general direction they might misinterpret it as an incoming nuclear first strike and retaliate accordingly. A very dangerous game.
Also it's rather pointless to deploy any sort of "drone" from a long range ballistic missile. It would need a complex and heavy braking system to slow down enough during re-entry to allow for controlled flight. Easier to just hit the target directly with a re-entry vehicle.
The point is that AI has the power to change the ecology of war. Cruise missiles occupy a niche, and yet they haven't obsoleted combat aircraft, so clearly they aren't "drones by another name"--drones serve a purpose today and will continue to diversify (including a blurring of lines between "drone" and "cruise missile"). Anyway, this conversation has taken a defensive tone, so I'll duck out.
