Why did Elon buy SpaceX?

Why would someone like Elon Musk, a billionaire entrepreneur with diverse interests, choose to invest heavily in SpaceX? Was it purely a financial decision, or did he have a deeper, more personal motivation behind his investment? Was he driven by a passion for space exploration and the potential to revolutionize the aerospace industry? Or did he see SpaceX as a way to further his own interests and legacy? What specific factors led him to make this decision, and how has it impacted his career and the future of space travel?