Look how hard it is to get existing guns away from Americans.
Look how easy it is to keep new war tech away from Americans.
The American right is pretty stupid and don't notice, but the 2nd amendment could just as easily be interpreted to mean that any new wartime technologies should be in the hands of the citizenry. So armed drones, RPGs, all sorts of gun mods which are illegal for the public.
The people will freak out if you try take what they have. They may not notice if you take what they could otherwise get. Vaping is new. Very few established old rich people vape. Take it now before today's youth become tomorrow's middle class.