Pop-Tarts are a cheap, readily-accessible, easily-consumed source of calories with a long shelf life that most people will at least tolerate. They're nutritionally incomplete, but they will help keep you alive and functional in the short term.

Most people don't stock up on MREs and survival bars, nor even have a clue where to start. Under such circumstances, it's both expected and reasonable that they reach for a familiar, readily-available energy source.

I remember hearing an anecdote many years ago that when food supplies where being dropped over Afghanistan it was the pop-tarts and peanut-butter that were the most popular.

I just looked into it and I the only information on their popularity I could find was that they are often sold on black-markets. Source: http://www.foreignpolicy.com/articles/2011/10/10/stuff_we_do...