Your point underscores two alternative "geopolitical feedback loops":

A) In the eyes of the average citizen, government fails to adequately distribute oil revenues. Result: violence, lower production & exports at higher cost.

or B) Government does its best to use oil wealth for the benefit of its citizens, and in doing so realizes that limiting production now to a certain extent 1) maximizes revenues, and 2) preserves oil wealth for future generations when it will likely be more valuable. Result: lower production & exports.

It's not a strictly A or B situation, but the danger (from the sense of oil supply) of avoiding one scenario is that the alternative may be just as bad, or worse... I agree that A is the most likely, but what happens if MEND "wins"? While they may fail at pursuing their own best interest due to corruption, short-sightedness, etc., their best interest may actually be to maintain lower levels of production...

Not to mention if you take option B, the US will call you a tyrant and accuse you of supporting terrorism. :)

More, the US (and the Western countries generally) and their corporations have systematically corrupted these gov'ts in order to get the oil (and other resources), and then turns around and calls them -- yes, corrupt -- when they in any way don't fully comply.

With respect to your (B) scenario, I'm skeptical that a government or rebel group would regard offshore oil operations as stable enough in the long term to consider saving those reserves for future generations. In the coming oil-short era, the country could easily lose access to offshore assets.

Onshore oil could more plausibly be kept in reserve. Sure, it could.

In the government's place, I would want to pump as much as possible from the offshore fields, then invest the resulting cash in some modernization project inside the country.

The plan is simpler than that.
Pump oil as fast as possible.
Deposit money in Switzerland.
Leave when there is nothing left to loot.

This is exactly the issue. I'm not saying that (B) is a likely scenario (rather, I think that A is far more likely in Africa), but just pointing out that (B) won't necessarily improve the export situation either. It would, I think, greatly improve the lives of the locals, but but it violates one of my laws of human behavior: any solution that requires many people to suddenly behave better than they have in the past is doomed to failure...