I think that greed is one of the contribuors to it. A while back, you wouldn't design a product if you knew that it would make others suffer/die, but now all most companies seem to care about is money, if they make money from it, they couldn't care less about what it does to the enviroment.
Car manufacters can easily avoid this by making hybrids. If people think that a certain model will damage the enviroment less, and therfore help them feel less guilty, they'll buy it. So the manufacters can make gas-guzzlers, with a AAA battery hoked up to the engine, call it a hybrid, and make money (that being their favourie bit).