No, you’re wrong.
It was NOT optimism that made him do that. He EXPECTED both Tesla and SpaceX to fail. Why he did them was because he felt it was important to humanity. The reason why he poured every cent into them in 2008 is because he NEVER gives up. EVER.
You don’t know the man at all.
Further, people do not verge on a nervous breakdown at the time of their optimism.
He knew if he only funded one the other would fail. If he funded both, both could fail.
One of the reasons I support Tesla in my own small way is the personal cost it has taken...