A fully reusable Starship has a launch cost of around $75m - $90m and the last V3 launch managed 44 tonnes of payload on a sub-orbital flight of not even 200km (Starlink satellites have an orbit of around 550km). That's an optimistic launch cost of $1.700/kg for a rather meaningless altitude and assuming a fully reusable Starship that doesn't keep blowing up.
I have no idea where you pulled your $400/kg number from, but it's complete and utter nonsense. To be economical at all, Starship needs to reach its target capacity of 100 tonnes to orbit, which is simply never going to happen. But even if it somehow does, it's physically impossible for Starship to ever make it further than the moon, at extreme costs, due to the refuelling requirements and fuel boil-off in orbit.
I have no idea where you pulled your $400/kg number from, but it's complete and utter nonsense. To be economical at all, Starship needs to reach its target capacity of 100 tonnes to orbit, which is simply never going to happen. But even if it somehow does, it's physically impossible for Starship to ever make it further than the moon, at extreme costs, due to the refuelling requirements and fuel boil-off in orbit.