I don't think the reason is unknown. You already stated the reason: it's an easy problem. Not just an easy one to solve, but an easy one to ignore because it's not just an easy problem, it's a small problem. It causes very little trouble, there is little loss of productivity, there is little to gain by solving it. It hasn't been fixed the way a ding on your car's door doesn't get fixed. That doesn't mean it can't be fixed, but I agree with OC's question, do we have so little other stuff to worry about that we have to go around looking for "problems" so small that most people didn't know they existed until they were told?

That reminds me, I wrote about this after seeing quite a few companies like this at TC Disrupt: http://techcrunch.com/2012/09/14/how-to-disrupt-petty-inconv...