A little bit of a tangent, but my kids often ask this sort of "why don't we just..." question. As some examples, why don't we just:

...send landfills to the sun to burn up ...use a wind turbine on a car to generate electricity ...ride horses instead of cars ...give everybody free houses/clothes/money

I always try to explain the science while not discouraging creative thought. It's hard, because I want to be sure they grasp the cold, hard truths of physics and economics, but I don't want to pigeonhole them into thinking "there will never be any solution to this problem". I've often thought a well-written "why don't we just" book or website would be engaging for kids and adults.