The stocks aren't really comparable. If you liquidated the companies GM would bring in many times Tesla. Tesla's value comes with a huge risk premium. Tesla was very close to going under a few months ago and it could still do so, if it doesn't execute right.
Do you really believe he couldn't raise 4-5 billion by calling friends at Google who share his vision? He wouldn't want to dilute his holdings, but if push came to shove he'd do it.
