Many angles of attack = many possible defences
Remember, the problem isn't purely technological. I consider that a good thing, because it means that changing the way people think about security could go a long way toward tightening things up.
One of the most common ways for the bad guys to get sensitive information is to ask for it, or for something that'll give them access to it. The most secure system in the world is an open house if the keys to the front door are given away for the asking, and it's staggering what some people are willing to give away.