Gates has no teaching experience and no academic credentials in education. We should listen to him because... he's rich? Any 22 year old first year teacher is more qualified to set education policy.
Gates may have not finished his schooling and may not be an educator, but he does talk to educators and people who know education. I think that's where he's getting his foundation for his ideas from.
He still has no experience in education. Trust me it's not something you learn from talking to educators and people who know education. I have spent years of my early career developing educational software and would not dare to imply I am as qualified as the educators and psychologists who worked with me.