Economies of scale at every stage of the game. Fuel is basically the cheapest part of a launch. Last I checked, the cost of maintaining infrastructure was on ro

Economies of scale at every stage of the game. Fuel is basically the cheapest part of a launch. Last I checked, the cost of maintaining infrastructure was on roughly the same order as the fuel per launch. More launches per site drives the cost-per down. Reusability is a spectrum. Falcon requires a nontrivial amount of inspection and refurb between launches, while Starship is aiming for jetliner levels of prep. Musk is also aiming to drive down the capex costs as well. There's less complexity for unmanned cargo hoist missions. I think the target for Starship is low tens of millions USD, basically cheaper than Falcon Heavy, but more reusable, with more capacity. I think the only thing that's not cheaper, is liquid methane is a bit more expensive per kJ. They are roughly the same price per kg, with RP-1 being more energy dense. But then again, I could see SpaceX vertically integrating and driving that cost down too.