Of course it's extreme, you don't get a quick solution with meek actions. And of course it wouldn't pass, it's certainly an overreaching law. However, it is probably the easiest, quick, solution to irresponsible gun ownership without taking away all guns, assuming perfect implementation. If you want a long-term solution, then changing the culture to enable changes to legislature and personal responsibility would be the most comprehensive solution.

And the death penalty is inefficient, in America at least, not necessarily expensive. It's expensive in general to punish criminals, but the amount of money spent to maintain execution methods and the amount of criminals it's actually used on makes it one of the most inefficient methods we have for punishment. However, it's also expensive to not deal with irresponsible gun use, as the disruption caused by crime, injury, and death probably lead to greater losses of money than it takes to maintain the death penalty. I don't have the exact numbers on either of them, so I'm just guessing at the extremity of the last point, but there are certainly economic losses to be had from irresponsible gun usage.