Can you explain why? Neither needs dancing robots, and both seem capable of building things themselves if they need it?

Robotics seem like a natural extension of space travel or transportation to me. Or maybe I just associate crazy high-tech stuff with Musk.

Tesla wants self driving cars and space shuttles that control themselves. Robot dogs are not that helpful to either. Maybe for Mars rovers, but I assume he thinks he can do better.

>Considering their current market cap, it surprises me that Tesla or Space X didn’t pick up BD.

Perhaps companies are leery of accepting Tesla's inflated shares as currency in any deal. SpaceX is still continuously raising cash, so I doubt they have a billion dollars to spend willy-nilly.

If they were, they could still sell them off immediately.

Usually, there are lock up periods for those, plus the uncertainty between when the operation starts being discussed, an agreement is made and shareholders approve. What will Tesla be worth in a year?

I doubt they would allow that.