If Russian tanks are vulnerable to drones how can the same be said of any of the places you describe?
Even if you think that this can somehow be circumvented with improvements in drone technology, think about who has an easier time using it - the state or would-be assassins.
After 9/11 all major wealth epicentres really started taking security a lot more seriously beyond just plain robbery.
Comparing them to out dated and corrupt armed force is selling them short.
But let's say that it isn't. Just for the sake of argument.
Will it still hold against $100 drones? $50 drones? $10 drones?
History is replete with examples of lessons of the eternal struggle between offense and defense. While we have come of age in a time where defense has conquered offense there is no guarantee that this will remain the status quo.
If we are entering a period where offense exceeds the capabilities of defense how will the wealthy respond? In the age of technology destroying the status quo is there any reason to believe that this will extend to the status quo of the wealthy having an advantagous defensive posture?
What does the future where anyone can fuck someone elses shit up without regard to their social status look like?