Why aren't shoes made for walking?

I recently bought a new pair of black flats. They're driving moccasin style, but they missed the bit where the sole goes up onto the heel.

This is a problem. About a month and a half and maybe twenty miles (but probably less) later, I've worn through the shoe. Not the sole. The bit where my heel strikes, through the upper of the shoe.

They weren't expensive, but that's not the point. They're shoes. I should be able to walk in them.