Our track record of defeating armed insurgencies is miserable. You’re also overlooking the nature of waging war on your own people. The military will follow a tyrannical dictator, until it doesn’t. In Bangladesh, for example, Pakistan killed hundreds of thousands of disarmed Bangladeshis. Thanks to smuggled arms from India, Bangladesh was able to put up some sort of resistance. Eventually, Bangladeshi members of the Pakistani military defected. Bangladesh could never have defeated the military with individual arms alone, but had they not been able to start a war they may have been brought into submission before pushing the military past the breaking point.