There is a fundamental problem with all this that Elon is well aware of and mentions often, but never speaks about the relatively near term implications (for obvious reasons).

Ultra-low fertility means the working/consuming age population is already dropping in ALL countries where people can afford Teslas & Optimus robots (other than Israel). And it will continue to drop increasingly rapidly for the next 60 years, at least.

Even if current downward fertility trends were to reverse right now it would take at least 30 years to reach replacement fertility & then small childbearing cohorts would still lead to shrinking consuming age population for another 30 years.

But the downward trends are getting worse year by year. Not just Europe & East Asia but North & South America & Islamic world too.

The global growth model is ending.

It simply cannot be maintained in the face of rapid demographic decline. Fewer consumers means fewer sales; fewer sales means less revenue; less revenue means lower profits & increasing losses; this tanks stock prices & leads to less investment. Less investment means less innovation.

Its a vicious, self-reinforcing downward spiral that leads to a Dark Age.

Only companies (like Tesla) producing products that currently don't exist & become 'must have' (like an iPhone in 2005) will be able to grow.

Companies producing things people already have, especially those with long lifetimes, are in deep trouble. Robots can produce widgets by the millions but who is going to buy them.

Robots & AI can produce, but only People consume.

Musk is a race against time to colonise Mars before the human capital that is needed (millions of talented, motivated, youngish people) becomes such a scarce commodity that it becomes impossible to attract it.

The depressing reality is that Optimus Robots's main role may be adult diaper changing.