Lets see here. If I read it right, the majority of posters are confident in their gun. Be it for reported high reliability or because it was the purchase they made, thus it must be the best. It is believed that their gun will work, no matter what, to solve any self defense problem.
Worded differently, how many people are less than completely confident with their carry gun? I notice a few folks with a backup plan, but not many.
Because you have smoke detectors and fire extinguishers, do you ignore an escape plan assuming those will completely solve your problem?
Another already stated it pretty well. The brain should be your first weapon. Firearm would be second. Then after that, I have a couple knives on me, depending on what I am working. Then if all else fails, I have a Leatherman Multitool, and if THAT fails, well, then I know some combatives.