I believe we are already living it. It is happening right now after the introduction of services like Whatsapp and WeChat. And all due to their simplicity and user friendliness. They just work for 99% of most modern world daily tasks, and solve a whole bunch of problems one way or the other. So maybe the real challenge for personal computing is connecting these wonder tools to everything else in world that is still complicated or hard to use, making them easy to use or accessible.