It seems to me that these guys are taking the SpaceX approach--don't look for what's best, look for what's the cheapest way to get the job done. That's why alm

It seems to me that these guys are taking the SpaceX approach--don't look for what's best, look for what's the cheapest way to get the job done. That's why almost all orbital rockets have used hydrolox for at least the upper stage but SpaceX uses kerolox. Hydrolox has substantially better performance but brings with it a whole bunch of handling headaches. SpaceX uses a lot more fuel to deliver the same mass to orbit--but fuel is a tiny percentage of the total cost of a space launch. The penalty for not using hydrolox when you're going beyond low orbit grows even greater--but SpaceX is figuring that with Starship they can ship up fuel separately and still get more throw weight per dollar. Even now, note how a fully recovered Falcon Heavy launch is cheaper than an expended Falcon 9 launch even though it uses 3x the fuel.