I mean I dunno if any internal numbers are meaningful at all as anything but accounting fictions. But the cost of the falcon 9 to external customers is believable, even if they are potentially subsidized by funding rounds, and impressive. Near as I can tell it comes from accepting trade-offs: they accept low specific impulse and thus declining performance at high velocity for cheap engines, they accept an overpowered oversized upper stage to have only one engine assembly line and to shift some of the burden to the upper stage that optimally would be on the first without reuse, they accept that entering at 2 km/s is way easier than entering at 8 km/s and don't try to recover the second stage, they accept the steep payload penalty of recovering the first stage. Starship on the other hand tries to brute-force through every trade-off - meaning theyre trying to push their engines through all sanity, the second stage is heavy and bulky and comically oversized, and theyre trying to have a big empty fuel tank be a heat shield which not even the shuttle ever tried.