Credit: Kiyoshi Ota / BloombergThe Economist has quantified the better (Ms Winfrey, Mr Yanai) and worse (Mr Burns) sorts of billionaire wealth. We call a billionaire’s wealth “uncompetitive” when it mainly comes from industries such as gambling, construction, defence and raw materials. From 2001, when our data begin, to 2014, the uncompetitive share of billionaire wealth rose slightly. Yet even excluding tech, the self-made billionaire share is rising. The third factor is mobile-first internet, which took off in the middle of the 2010s — just as the self-made share started to rise.