When you are attacked, just dial 911. That will fix everything.
Or, you can take the Jim Webb approach: Don't attack me-- I have a loaded gun and I'm not afraid to use it! Once I find it, that is. Wait, it's in my other car-- or did I give it to that guy at the office?
I agree with you that an unloaded weapon is virtually useless for protection. I hope you agree with me that a gun several states away, in someone else's possession, after you misplaced it in one of your three cars, is equally useless as protection.
I don't keep guns in my cars. I wear my carry, and transport guns to the range. When at home, there are three loaded guns and the rest are stored in my gun safe.