First, it's been about to collapse for decades. We keep being about to run out of oil. For my part, I think there's a lot more fracking that will happen if the price rises much farther. Oil therefore may rise a bit, but will continue to be available at a non-ruinous price (speaking purely economically here).
Second, renewables are close to being able to take significant load off of fossil fuels. Already coal use is declining (at least in America), and not because coal got scarce or expensive.
