They cant outlaw guns (lets not pretend) because humans have the inalienable right to -defend- themselves. And that includes against a tyrannical government. The United States would not exist otherwise[1].
Given the way you're intentionally missing the point, I think it's clear my argument hit the mark. And jutt to further clarify, it's completely possible to ban things that someone can manufacture. I'm not sure what makes you think otherwise.
[1] https://s3.amazonaws.com/oyez.case-media.ogg/case_data/2007/...
You cant outlaw lathes and mills. Now guns are now printable. That train has left. DRM lost.