The biggest force behind the startup bubble in the United States has been SoftBank Group (SFTBY) (SFTBF), the Japanese publicly traded conglomerate. It has been the biggest force in driving up valuations of money-losing cash-burn machines to absurd levels. It has been the biggest force in flooding Silicon Valley, San Francisco, and many other startup hot spots with a tsunami of money from around the world - money that it borrowed, and money that other large investors committed to SoftBank's investment funds to ride on its coattails. But the scheme has run into trouble, and