I think that analysis fails to properly understand the way people in the US think about guns.
Many, many people will tell you that the 2nd Amendment is absolutely required to protect against, and keep in check, any nefarious government/military actions. There's even some wording about it being required to be a free state. The vast majority of these people are also safe, law-abiding gun owners - the only threat they pose is in the general increase in gun numbers.
These people absolutely will not be giving up their guns within the planning horizon of any government action. They won't be convinced by events like the ones in this thread, because they are the responsible owners. They won't be convinced by the fact that other countries don't need them because we simply don't understand their concept of freedom and haven't had to fight for independence as recently as them.
It's not an opinion I agree with, but it's one I understand.