Both of your statements here fail to acknowledge the path a gun takes from the manufacturer to criminal.
Typically, a gun is stolen from a legal owner, then sold on the black market.
Your plan ignores a simple law of economics: Supply and demand. Demand (particularly from criminals) won't be reduced by your policies, but the supply will. Coupled with a price floor (your buy-back program), you'll essentially drive a market for stolen guns. The black market price for a gun will skyrocket, perhaps even to the point where criminals are willing to take the risk of knocking over a cop for his gun, to say nothing of the ones in his cruiser.
This will, of course, result in reprisals, and even more violence on the streets. You thought the drug war was bad? Just wait til you see the gun war. (and that's
without the inevitable corruption, and supposedly "destroyed" guns showing back up on the streets.)
Actually, it all works quite well.
An increased risk of losing your gun to theft means you're less likely to be careless about it. You won't carry it on your person. You'll lock it up in a safe. You definitely wouldn't want to lose your gun, or be careless about it, because with limited permits being issued, you might not get another for a long time.
Criminals will be less likely to afford them, given the prices. Sure, they'll attempt to steal them, but the reality is, stealing them will be really hard, because those who possess guns just won't let them get stolen.
And finally, criminals will be tempted by the high prices to get rid of the ones they do have, hopefully to sting operations and/or gun buy back programs.
In the end, culturally, the gun nut crowd will realize that guns are not trivial things that should so easily be lost, misplaced, exposed, left inside a drawer or a car, but instead properly locked up in a safe. Given time, gun culture can fade away, which is ultimately what is necessary.
Because the very basic facts of the current situation is there are entirely too many guns out there, and adding more to the mix only makes the probability of criminals being in possession of them more likely.