One argument I rarely see mentioned: there are basically two Nash equilibria in the problem, one where gun ownership is sparse and one where it is very common.

If I live in a country with very few guns around, say most of Europe, I'm probably better off not having one - it's common for gun owners to be killed with their own gun in a melee, for example. If, on the other hand, any burglar or opportunistic petty criminal has a handgun, I guess I may need one too.

Now, jumping from the "lots of guns" equilibrium to the "few guns" equilibrium, even if you have societal buy-in, is hard - how do you collect all the guns from bad actors who don't want to relinquish them, when there are so many? Maybe it's so hard that it's infeasible (steel man alert) and so you're better off perpetuating and strengthening your gun ownership laws.