I can't guess why Bezos does what he does but have to give him credit for not going the Soros route...WP aside of course.

If I were him, I'd avoid anything Musk (who sucks all the air out of the room) is involved in. Build the worlds biggest telescope, work on advanced propulsion technology for launch or interplanetary spacecraft, there's a lot of cool things out there. I doubt that the first investor in anything really cutting edge is going to make a profit, so look for the wow factor.