What I don't understand is how Jack Dorsey could believe he could successfully manage two companies, Square and Twitter, at the same time at such critical point

What I don't understand is how Jack Dorsey could believe he could successfully manage two companies, Square and Twitter, at the same time at such critical points in their growth. I just shake my head at the unbridled hubris and over-estimation of one's own abilities that one must have to make this decision. It's very frustrating, because I believe both companies could be so much greater at what they do; they've just touched the tip of the iceberg. The gentle explanation: He's an external figurehead, and he has 3 rock star execs supporting him, each of whom has CEO-level capabilities. (Noto, Bain and Kordestani) The less gentle explanation: If you think you're the second coming of Steve Jobs, part of securing your legacy is starting a company simultaneous to turning around your old company. It ain't easy being Steve Jobs! Either way, it doesn't look like it's going to end well.