There’s lots of things that are just too big and heavy and need launch vehicles like that.
It might be overkill for satellites, but space stations and habitats need the payload capacity of something like this to become anything resembling economical.
A bit like asking how many 30 story buildings are there when we first started building modern steel and concrete buildings. How many cathedrals could we possibly need?
If we're to build a Moon base, we're going to have at least this frequency of flights - really, I'd prefer to have a great margin on top of that, because Moon is much harder than LEO, and we might need more resiliency to safely explore.
Each flight to the Moon will likely need to involve 10-20 Starship flights (rough number) to LEO. So even if we're flying twice a year - and 6 month stay on the Moon right now looks like a pretty serious expedition - we need to have a Starship flight every ~10-15 days.
So even for a robust Moon exploration program we need as many Starships per year as the whole world was launching rockets per year just some ~20 years ago.
Mars launch window is every two years. It is very inefficient to launch at other times.
As for moon, I'm surprised with the estimate you have provided. Apollo needed just one launch for each mission. Even if SpaceX will do orbital re-fueling, it's just two-three launches, why would you need more?
BTW, the idea of getting heavy Starship to the moon and back is interesting, but at the end flying the vehicle optimized for re-entry far away and back is suboptimal. My prediction that they quickly will go to specialized LEO-LMO vehicles with LEO re-fueling.
> Even if SpaceX will do orbital re-fueling, it's just two-three launches, why would you need more?
Wikipedia says Starship weights 120 ton empty and 1320 ton fueled, plus 100 ton payload (approximate numbers). That means fuel weights 1200 ton. So to carry fuel to LEO to fuel up a Starship you need 1200 / 100 = 12 flights. You can change this number maybe 2 times into both directions, but I doubt you'll fuel Starship with just 2 or 3 flights of tankers. Would be glad to err here.
But you don’t have to fuel it fully to go to the moon and back.
It’s a bit hard to compare to Apollo since Apollo dropped stages at every step of the process, but it seems they used 70 tons of fuel in the third state of Saturn V for original trans lunar injection of 45 ton Apollo. Apollo itself was 2/3 fuel. So it’s ratio of 15 tons to 90 tons. I.e. 1/6.
> But you don’t have to fuel it fully to go to the moon and back.
Numbers: from LEO (low Earth orbit) to TLI (translunar injection) - approx. 3.1 km/s; from Moon hyperbolic to LMO (low Moon orbit) - approx. 0.8 km/s; from LMO to the Moon surface - 1.6 km/s, back to LMO - 1.6 km/s, total - 7.1 km.s . Numbers are optimistic, no errors. You absolutely, positively have to add delta-V for landing, Apollo LEMs, for example, had ~0.6 km/s, and also for docking - about the same, so total is already 8.3 km/s . This is more than Starship needs to get to LEO after SuperHeavy boosted it from the Earth.
So... no, if you're planning to get to the Moon anything near the Starship regular payload - 100 ton - you absolutely have to fuel it up fully.
> My prediction that they quickly will go to specialized LEO-LMO vehicles with LEO re-fueling.
Two comments here. First, we assume now SpaceX is going to have Starship HLS - human landing system - which doesn't go back to Earth, doesn't have flaps or heat shield, and is going to be used between low Moon orbit (LMO) and Moon surface - maybe one roundtrip, maybe more. Yes, for each following roundtrip HLS needs to be refueled.
Second, Musk mentioned "Moon base Alpha" in his talk. Having a serious Moon base makes it possible to produce some of propellants there. Oxygen is plentiful in the form of oxides on the Moon, and by mass it's 2/3 - 3/4 of the propellant load of the Starship, so it might be useful to produce it on the Moon.
It might be overkill for satellites, but space stations and habitats need the payload capacity of something like this to become anything resembling economical.