If it were that easy for an occupying power to shut down a guerrilla war, wouldn't it happen all the time, instead of virtually never? You might want to put down your Jane's Awesome Weapons book and look for the commonalities in occupied territories, and why occupational wars just don't win. Sure, big air power bitchslap that blows up all the tanks, whatever. How many times are we going to have to watch this play out again, before it's understood that the opening attack is not the whole war.
I can't tell if you're just ignoring 99% of the content of my posts or just not reading for comprehension.
The entire paradigm the US military has been following throughout the Cold War was that of dominating a conventional army. As a result, they do that
incredibly well. This has been at the expense of developing means to effectively occupy territory filled with hostile civilians and small, poorly trained and equipped, irregular militias. Because, quite simply, the ability to wipe out an entire tank column with
one bomb doesn't mean shit when your only resistance is a bunch of untrained kids with old AK-47s hiding in the middle of a slum. Now, those kids aren't going to be able to stop you from setting up a fortified encampment in the middle of the city, but they can take potshots at any soldiers you send out through the streets, which you need to do to root them out in the first place. They're going to make things unpleasant for you, sure, and present a barrier to pacifying the region, while being almost impossible to uproot completely (after all, you can kill them all you want, but it's not like an untrained kid given a cheap gun and told to shoot at the tanks is very hard to replace) but they can't do more than scratch even the most vulnerable parts of the operation. The only way to stop them is to dry up their well of recruits, or capture/kill the only competent leaders they have so that they end up increasingly irrelevant.
NK has a conventional army, which would be the main barrier to an invasion by SK (whether or not they would
want to invade is irrelevant to that fact), and the main threat to SK (aside from NK's theoretical nukes). In fact, I dare assume that it's almost
exactly the army the US military was designed to counter, given that it would be old chinese equipment based on even older soviet equipment. So it, on its own, wouldn't stand a chance in hell against the modern US arsenal. Now, actually invading would be more problematic, but it would still mostly amount to mopping up the broken, scattered remnants of the NK army by the SK army. Now, some would probably have the good sense/luck to be hidden away in the ass end of nowhere, not presenting an immediate problem to the task of occupying population centers, which could conceivably end up as guerrillas. Unless they're actively recruiting from the populace, they would dry up after a while (because, counter to the romantic notion of an untouchable superman that slaughters the better equipped soldiers in droves before fading into nothing to strike again elsewhere, guerrillas die. In droves. Tactically, guerrilla warfare is nothing but using heavy cover of one kind or another to ambush a small number of enemy soldiers, before running away in that heavy cover, or ambushing supply lines before running away again. Still plenty of opportunity to die in all that), without a government backing them.
Guerrilla wars only "win" when the country is in ruins and the occupying force has decided that it's not worth the operating cost to keep up a military occupation. Or, alternatively, when it's a militia backed by a foreign power against a two-bit dictator who lacks the manpower to stand against it. Neither of which apply to SK occupying NK. (Fuck whether or not it wants to. I'm talking about the strategic viability of doing so, not the political (although, if the situation were to explode
not occupying it wouldn't be politically viable, especially not after NK fell apart. The alternative is china swooping in, which would be worse for everyone but china))