Difficulty: the "populace" is everywhere.

If you own everything, and you bomb the populace, you bomb your own stuff.

If everybody works for you, and you bomb the populace, you bomb your own serfs.

And those faceless individuals who are actually holding the weapons, and actually know how they work, and actually know, in a detailed, hands-on way, how to do coordinated violence with them? It turns out they're secretly members of the populace. You'd better make sure they think it's in their interest to keep using the weapons the way you want them to.