Entire divisions of the British Army could not find or subdue a couple 100 “active IRA” during The Troubles in Northern Ireland.
The IRA could have easily turned off the power grid on a weekly basis, if that had been their desire. Or sniped at food delivery trucks.
The Brits quit and went home when the IRA took their campaign to London.
Northern Ireland (Ulster) is 2 million people on 8,000 square miles. That’s the size of New Jersey, which has 4X the population.
The British Army quit and went home.
The US military could not in a thousand years save or restore order to or feed a dozen imploding “American Beiruts.”
The IRA is an excellent example of an intelligent home field advantage against a government. The IRA kept that conflict going for decades. As you said, if they really wanted to go further they could have.