Alexandr Wang is living the classic Silicon Valley success story. At just 23 he's the CEO of Scale AI, a four-year-old company valued at $1 billion that he founded at age 19, dropping out of MIT to do so. His company is building tools for AI developers trying to do for AI tech what cloud computing did for software development, building the infrastructure that makes it easier. And it's attracted a Silicon Valley who's who of angel and venture investors.