The geeky dropouts with wild ideas have to rope in venture capitalists befo re they can take over the world. The US has a lot of venture capitalist, an d a tax system that makes it practical to bankroll at lot of adventures whe re only one in ten will even pay back the ventured capital.
Australia has a couple of new millionaires who had to go tho the USA to get backing for their particular wild ideas.
Of course the only one of my friends to take over even a small part of the world (with a better confocal microscope) got his backing from another Aust ralian who had made his fortune in America (with a better patch-clamp elect rode) before he came back to Australia.