If 8.1 billion people marched on a government, even with a full array of advanced and nuclear weapons in their arsenal, would they still definitely lose? What about one billion? A hundred million? Ten million? Where do you think the line is?
Caveat: The government does want to be able to live on earth again within their lifetimes, but can spend up to a year in bunkers, and the military doesn’t revolt- given that nuclear weapons can be deployed by one person, the worst option doesn’t even really require the military’s cooperation.
Certainly as you approach 8 billion, they’re more disorganized, but they’re not ever an actual militia, more just a horde of people all trying to help each other dismantle any relevant infrastructure and kill/disable any soldiers sent to suppress them. No training, but absolute solidarity.