I'm in the melancholy place of agreeing with your measures but feeling I need to shoot down (where did I get that metaphor from?) most of them down.
First, yes, serious gun bans are a sort of political third rail no one wants to touch.
Military assault weapons (fully automatic) are banned already, but there are several loopholes which allow gun enthusiasts to fiddle with semi-automatic weapons and make them fully automatic. There is also a lengthy application process that will allow owning an automatic that was manufactured before 1986. Suppressing such alterations and exceptions is an endless game of Whack-a-Mole, AFAICT.
State bans are a start, but ultimately are weakened by the high porosity of our state borders.
As for the justification for having anything beyond a deer rifle or a handgun for home protection, it is a sort-of "what if" form of justification. What if we banned assault-style rifles, would that be a slippery slope to cancelling the 2nd Amendment and all gun rights? What if maurauders burst into your home with assault-rifles, you must be able to match their firepower! If we allow strict gun controls, we will allow a godless Maoist brigade to follow them up by stamping out religion and red meat and then putting us all in reeducation camps where we're forced to love trans people and tofu!
IOW, what is conjured is a sort of zombie army of strawman arguments based on extremely rare scenarios or highly improbable future hypotheticals. A more honest argument would have been "We love guns for the tradition of rural self-reliance they represent, they help us feel our rural culture has not been swallowed by the urban Borg Collective." But that's not a terribly compelling argument.
So those who would like to see us move towards a Euro/UK/Japan model of limited civilian gun access live in a zone of lowered expectations and tiny increments of change, if any. Any real change would be a vast cultural shift, the kind that tends to take many lifespans.
