What would happen if one of the major European powers (Britain, France or Germany) took control of the Persian Gulf in the late 19th Century? With two thirds of the world's oil reserves, would that not make them insanely wealthy?
Maybe not directly but wouldn't they of taken their share of the profits of companies like the Anglo-Persian Oil Company? Considering how cheap indirect rule was I'd be surprised if they didn't break even or at least run at only a minor loss.