You cannot expect to be able to remove every single weapon. When a criminal wants to use a firearm, they will get it. The more guns in law-abiding civilian hands, the safer our country will be. Whenever you look at places where firearms are required or open carry is allowed, the crime rate is nearly zero.
Think about it: if you wanted to rob a bank, but knew that just 10% of the people in that bank were possible CCW permit holders, how likely are you to continue with your plan? Oppositely, if you know that there is a low chance that even one person, including the guard outside, has a weapon, and LEO's are 5-10 mins out, things look much better for your heist, don't they?
You know, it baffles me; I was listening to the radio, and a lady called in. She immediately stated her intent to push for a complete ban on all firearms. The host asked her what her plan was if her house was broken into at night while she was in bed, and the robber was armed. Her response: "My husband and I would grab our cellphones off the headboard and roll off under the bed and wait for police." :rofl: