As I mentioned, they’re not going to start pouring money into that until they’re sure there’s a point to doing so. At worst, the first stages of a Mars base could consist of basically operating the ISS on Mars’ surface, 100% dependent on consumables shipped from Earth. That could continue either until the technologies needed are developed or until they give up.
I don’t doubt Starship is currently a huge money pit, probably huge enough that SpaceX doesn’t want to scare off investors. But we do know what SpaceX charges for Falcon flights and I doubt they’re doing it at a loss. We’ll know how cheap or not Starship is when SpaceX starts accepting payload bids for it.