Here is another chart.
https://www.vox.com/policy-and-politics/2017/10/2/16399418/us-gun-violence-statistics-maps-charts
(chart 6 for reference)
If the US cut gun ownership by 80%, and still managed to be the worst nation on the chart (by only reducing gun deaths by 30%), I think that would still be viewed as a massive accomplishment and people would worry about cultural factors later.
For the life of me I can't see why you wouldn't advocate precisely what you've you've just speculated about, given the obvious conclusions from the charts/ graphs you link to.