Even if this turns out to be true, it would be irrelevant. The reason that oil occupies the geopolitical role it does today is because of its potential to rapidly bring the entire developed world to a halt. Oil will always be in demand because of its many useful applications (and this demand may even grow in absolute terms despite declining per-capita consumption, because the global human population is projected to continue increasing well into the latter half of the century), but as an energy source, by 2050 it will have so many highly-available complements that an oil cartel will be as relevant as a potato cartel.