One of the interesting things about oil is that it is also subject to local price pressure even though it is bought and sold on a global spot market. I'll bet most folks don't know that there's actually a glut of oil here in North America. Quite simply, we are extracting crude oil from the ground faster than we can transport and refine it. That's why the price for West Texas Intermediate has been markedly lower than Brent Crude for several years -- even though WTI has historically been more expensive.
Plus the price of natural gas has dropped 80% in past few years because of shale. Steel and plastics are much cheaper to produce and will get cheaper.