Fracked oil from North Dakota peaked and declined deliberately because the world oil glut, which continues, took the oil price below the recovery cost. Every time oil goes above $50/bbl, the rigs start drilling, maintaining the glut. Why? because if drillers don't drill, they don't make money. It's as simple as that. But North Dakota has more than the Bakken, there are at least three equivalent shale formations below the Bakken, with equal prospects. The Williston Basin play can continue for at least another 50 years at near present capacity, along with other fields in the US, and there are numerous other oil shale basins around the world.

I'm not saying this would be a good thing, except for investors. I'm saying that as long as there is demand, oil will be around for the remainder of this century.