As to your point about militias and the national guard as it relates to the 2nd ammendment, I believe the supreme court ruled that the right to bear arms was an individual right, not a collective right. The national guard was founded in 1913 about 130 years after the constitution was written. I don't think the framers had the national guard in mind when they wrote second ammendment.
I disagree with a ban on firearm ownership, for many reasons. But even if I didn't, there is a shitload of illegal guns and ammo just floating around, you are looking at 50 years minimum before that is exhausted, and then only criminals will be using it.