You cannot control an entire country and its people with tanks, jets, battleships and drones or any of these things that you believe trumps citizen ownership of firearms.
A fighter jet, tank, drone, battleship cannot stand on street corners and enforce no assembly edicts. A fighter jet cannot kick down your door at 3AM and search your house for contraband.
None of these things can maintain the needed police state to completely subjugate and enslave the people of a nation. Those weapons are for decimating, flattening and glassing large areas and many people at once, and fighting other state militaries. The government does not want to kill all of its people and blow up its own infrastructure. They require these things to become tyrannical in the first place. If they decided to turn everything outside of Washington D.C. into glowing green glass they would be the absolute rulers of a big, worthless radioactive wasteland.
Police are needed to maintain a police state, boots on the ground. And no matter how many police you have on the ground they will always be vastly outnumbered by civilians which is why in a police state it is vital that your police have automatic weapons while the people have nothing.
BUT when every random pedestrian could have a Glock in their waistband and every random homeowner an AR-15, all of that goes out the window because now the police are out numbered and face the reality of bullets coming back at them.
If you want living examples of this look at every insurgency that the U.S. military has tried to destroy. They’re all still kicking with nothing but AK-47s, pick up trucks and improvised explosives because these big scary military monsters you keep alluding to are
all but useless for dealing with them.