Gloomy future of income inequality

Recent documentary film, "Inequality for all", gives a sobering reminder of the worsening income inequality. Famous Koch brothers earn $3M USD per hour (yes, per hour). Income increases a lot in the last 25 years for top 20% but stagnant for bottom 50% after adjusted by inflation. Income inequality started to go up in 1975, the year computer started to emerge. It is so scary that income inequality will be worse in the future since the whole world has started to become skill- and capital-centralized (just imagine that robots now cost $3.5 USD per hour!)