[badpun]

Large amounts of global inequality are because, to the very recent times, most of the people in the world lived under communism, which kept them in poverty (often extreme). The rest of the world was lucky to enjoy massive increase of standards of living thanks to capitalism, which created a chasm. Only now, as capitalism has spread to most countries, the global inequality is decreasing (see ex. increasing wages in China and stagnant wages in US).