That article seems to think that people are driven to prepare for the worst out of paranoia. I don't think that it's at all likely that I will even need my emergency food, water, or ammo, but I have it anyway. There are three factors that I consider for preparation.
How likely am I to need to utilize the preparation (stocks of ammo, food, water, etc)?
What would the consequences be if I needed it and didn't have it?
How much of a hassle is it to be prepared?
Everything that we're talking about (carrying a gun, storing food and water, storing ammo, etc) falls into the same set of answers to those questions. It's not likely that we'll need it, the consequences would be dire if we needed it and didn't have it, and it's not a hassle at all to be prepared. So why in the world wouldn't we do our best to be prepared, even if the even in question is unlikely? As the likelihood of needing it goes up (e.g. social turmoil) or the consequences of not having it go up (e.g. starting a family), the limit for how much of a hassle we're willing to tolerate goes up. It's all a formula. It has nothing to do with paranoia and everything to do with foresight and preparedness.
To answer the question, I wouldn't last long enough. I have food for a month, but not enough water to match that. I guess I should work on that.