Remember the Maginot line and how powerful and defensive it was going to be… And then the Germans just bypassed it? Remember the West Wall, where the Allies were going to throw themselves against in the waning days of World War II… And then it was not just pierced but effectively eliminated as a protective barrier in five days of fighting?
That’s what happens when you know you need a defense, and you place all of your eggs in one basket. At least in the IT world a little caution can save you a lot. Here’s a cautionary tale. We trust SSL explicitly, but from a “download random app X” perspective, that’s a mistake.