True, but you can't fight a massively distributed attack using a very small concentrated force of professional soldiers; hence the population needs to be issued with weapons and training in an emergency for civil defense.
Conventional weapons like tanks and fixed emplacements just become easy targets.
Why go through the trouble of using drone, just use a barrage conventional missiles, hypothetical country is unlikely to have anti-rocket system like iron dome
I'd assume systems like that require something like an army are regulated and in control of nation states. My point was something like a few hundred thousand drones could probably stealthily be acquired by a wealthy individual. If it's autonomous and remotely controlled you might not even know who's behind it
OK, but in this scenario, the wealthy individual is trying to do what? Take over the country?
Fine. Let him. When he does so, he quits being anonymous. Then assassinate him and restore the previous government. Bonus style points if you assassinate him with a drone.
IF that's the goal, a Neutron Bomb[1] would be far more efficient. From Wikipedia: "Lawrence Livermore National Laboratory director Harold Brown and Soviet General Secretary Leonid Brezhnev both described neutron bombs as a "capitalist bomb", because it was designed to destroy people while preserving property."