My guess is that he didn't start Tesla with the idea of using it as a (possible) cash cow for SpaceX. It was, as you said, to help humanity scale and survive.

What follows is definitely a bit more 'out there' than usual, and I don't hold strongly to it.

As Mr. Mush has gotten older, I suspect that his internal calculations related to the possibility of the collapse of human civilization have gone up enormously. Specifically, and he's said this multiple times, he thinks AI is the number one threat to human civilization, followed very closely by climate change. (Note: this isn't terminator style AI. It's software/hardware that is smarter than any human, or indeed all humans put together, but in the hands of very few people.)

My guess is that these have changed his perspective on the relative importance of SpaceX and Tesla in the greater scheme of things.

> Starship development should make the next few years just fascinating for us space nerds.

I am utterly pumped.