A $500-billion smart city. A $200-billion solar farm. Billions of dollars in investments in gas and petrochemicals. These were all facets of Saudi Arabia’s Vision 2030—perhaps the most ambitious economic diversification in the world. Now, that ambition is in tatters. Can Saudi Arabia pick up the pieces and truly diversify its economy away from oil, or are its plans dead in the water, leaving the Kingdom’s survival forever tied to oil revenues? Earlier this week, Saudi Arabia’s Aramco said it would shelve an investment of several billion dollars in Sempra Energy’s Port Arthur LNG terminal. It also said it would delay investments in a $20-billion refining and petrochemical project at home, at its Yanbu hub. The reason: cash conservation. Earlier this year, Riyadh government sources told the Wall Street Journal that Saudi Arabia was not pursuing its $200-billion solar farm project it had conceived in partnership with Japan’s SoftBank. […]