Yep. It’s a concept as old as Rome or ancient Greece: the citizen-soldier will answer the call when the security of the State is threatened. After fighting became too expensive and specialistic for this approach in the middle ages (when the necessary horses, good armour and heavy swords cost so much that the activity was basically limited to aristocrats and mercenaries), the concept was “rediscovered” with the invention of pistols and portable guns, which were easy enough and light enough to be usable with very little training. The Swiss had a couple of famous victories in this way and have maintained more or less the same approach since; the American revolution was indeed built on this same approach, like the French one would be a few years later, culminating in the Napoleonic armies.
It is pretty clear, knowing the historical context of the revolution, what that amendment was supposed to mean: maintaining the winning citizen-fighter model into the new states, but well-regulated since citizens were now fully enfranchised.
Also, at the time there was a real threat that Britain, France or Spain could re-invade US territories and a new insurgency might become necessary; that has not been a realistic scenario for over a century now. After the atomic bomb got in the picture, we can now assume that nobody would ever even try to occupy the US: any power fancying their chances to defeat the almighty US would just nuke it with ICBMs. Maintaining guerrilla capabilities in deep US territories is completely redundant nowadays, to use an euphemism. Being more honest, as we just saw, in reality it’s an actively destabilizing factor.
