You're right. The price going down has, I think, more to do with the effect of fracking in the US. It's getting to the point that the US could be an exporter if it changed its laws.
The effect of petro-states will be much the same, though.
The US, like everyone else in the world, will always be an oil exporter and an oil importer. The grades of oil differ throughout the world, and are used in different industries.
The effect of petro-states will be much the same, though.