Assuming that gas doesn't end up around $15/gal by then...
Unless we end up with refinery bottlenecks (like we more or less have now) or political incentives (although the odds of that seem alarmingly low at this point).
> The consumption would be lower so price would be too.
Is this expected to hold as oil usage drops over the next century?
My point is that there is relationship with price and consumption. If the price rises too much people will either look for alternatives or reduce use. Thus prices might not rise that much.