There might be a lot of induced demand from starship. I’m sure defense is a big one.

No, but really, where will it come from?

If (as seems to be the case) nobody can identify a specific source of latent demand that is large enough to soak up the two order of magnitude increase in the supply of heavy lift launch capacity that Elon wants to deliver, then that strongly suggests that SpaceX does not actually have a business plan for Starship. Or at least, not a business plan that’s been thought through as clearly as a $5 billion (and counting) investment would warrant.

“Defense” is not nearly specific enough to count as an answer. What kind of defense application, specifically, do you have in mind, and why does it need specifically this kind of heavy lift capacity to be viable?