I read it differently. To me the first clause is a statement, not an "if-then." So as long as the 2nd Amendment is the law of the land, it remains relevant. Not sure how anyone can dispute people's right to own and carry AR-15s as long as it exists.
According to your logic, anyone can own a nuclear weapon as long as it exists. 2A doesn't say you can't, eh?
Nuts to that.
A state and/or the fed gov has every right to regulate, which could include disallowing the ownership of AR-15s.
2A says "the right.......shall not be infringed". When you diagram the sentence, that is what it says, nothing more.
If you are going to argue "right to bear arms" as if it means an individual can own as many as he or she wants, note that it doesn't say that because of the fact that "arms" is merely a grammatical agreement with the other part of the sentence "the people".
In short, 2A gaurantees only the right to a firearm, nothing about quantity, type, caliber, etc. Such things are left to further regulation.
But, if you want to go to original construct, it was designed to apply to what was going on at the time, state militias, muskets, and conscription of all males into the state militia but as civilians, not "soldiers", and 2A was to protect the militia, and if you really want to get down to brass tacks, Madison put it in their so that Georgia and Virginia, who were afraid that the north were going to "take away their slaves" would ratify it because 2A protected state militias, which, in the south, was more about slave patrols than anything else. (there's still an ongoing debate about this premise, so I'm open to changing that position if someone can show me actual historical writings that will settle the issue, once and for all. I've read opinions of learned people on both sides of the debate and as of late, the above appears to me to be the more compelling argument)
Given that there is no longer a state militia composed of civilians (the national guard is composed of military personnel, not civilians, so 2A is not needed for them to "bear arms" ), it's therefore a moot amendment.
But, given that quite a few judges love to hunt, and couldn't imagine taking away people's guns, they have breathed life into 2A to apply to modern times and interpreted as a modern individual right. The didn't have to, there was nothing in 2A that dictated that interpretation given historical construct, but they did, and it's done deal, until it is repealed, if ever.