My take is, they tackle problems whose difficulty is increasing exponentially. Making a rocket that flies, from scratch, is X% harder than building one that already exist. Making it land again, X%. Reusing it, X%. I'm also skipping intermediate points here - like about the engines have a particular closed-loop design that is more fuel efficient.

Starship seems to, again, require a few of these X% improvements. And the thing about exponential growth, as Covid kindly reminded us, is that eventually it is overwhelming.

So I don't think you can simply extrapolate from "they have a good track record of solving hard problems", because the problems they tackle are getting harder and harder.

Yeah, that's a reasonable doubt, I'd say. Just not a strong one on its own.

Well, extrapolation is always poorly justified in the first place. Extrapolation where problems get exponentially harder is just speculation IMO.

I wish them well, but I'm tired of all these blogs writing about Starship as if it's a done thing, to the point of writing about delivery costs. It might happen, it might not.