But banns do increase the cost of obtaining something; and strength of penalty reduces likelihood of behavior.
gang violence would not use many guns if they cost 100x as much and simple ownership of a gun was penalized as "intent to kill".
Taking guns, though, from the populace would fail.
If saving lives is the dependent variable of interest, then you're right.
But saving lives that are lost without good cause is what's of interest; the deal with the devil for speed and convenience is something we're willing to make. Further, it is emotionally charged to lose one life at the hands of a gun-man; whilst losing a life in a car-wreck where you FEEL like you have control is much less upsetting.
My take:
There is, honestly, two americas: In one the inner city runs red with the blood of poor people paid to live on top of each other; in this america guns are fucking evil. In the suburban/rural america, guns are recreation, a hobby, something almost no one will ever use on another human, and less likely to kill someone than your back-yard pool is.
Look at who's on what side and why: liberals have poor inner-city folks as constants, they have a vested interest in stoping their self-genocide; conservatives have poor-rural and upper-middle suburban and well-to-do city dwellers, the poor-rural is driven by fear, upper-middle lives in a world where guns aren't dangerous, and well-to-do city dwellers rely on others to own guns to protect them.
Maybe my analysis is off; but it seems to me that "common sense" in the poor-urban setting is a whole different thing than "common sense" over in middle-class suburban.