>>510171659 (OP)The further you need to go, the more fuel you need.
The more fuel you need, the more weight you need to push into orbit
The more weight you need to push into orbit, the more fuel you need.
The more fuel you need, the more weight you need to push into orbit.
See the problem?
The issue is that the original moon rockets were designed from the ground up to push enough fuel into orbit to reach the moon. But the Starship is a proprietary mass-producible design made to move lightweight objects into orbit. It's not designed to carry that much weight, hence the need to divide it into several launches, making for an extremely inefficient solution.
The takeaway is that the Starship rocket is not good at things it was not designed to do, and that if a moon mission were a serious undertaking, it would be more cost-effective to design and develop a dedicated earth-to-orbit-to-moon platform that could carry the necessary fuel and weight in a single launch. In practice Musk is probably just making a pitch for more government funding, and I wouldn't really take anything he says at face value.