In the days of the commodity boom a few years ago, oil-rich nations and their petrodollar wealth were the darlings of the World Economic Forum. A panel that included Kuwaiti, Saudi and Russian sovereign-wealth fund officials was one the hottest tickets at Davos in January 2008, just before oil prices surged to $150 a barrel. It was a time when crude producers were accumulating billions of dollars in debt and equities, plus real estate, sports teams and other trophy assets. So, influential were the fund managers that a group of bank chiefs told them behind closed doors at the Swiss resort to ...