[avian]

> SpaceX solves that with refueling in low Earth orbit, that allows to scale rocket fuel needs linearly with regard to payload instead of exponentially.

I don't think that's the case. The rocket equation has the delta-v under exponent, not the mass ratio. Fuel mass scales linearly with payload in any case.

I don't think orbital refueling changes any scaling laws. It just means you can launch several small rockets instead of one huge one. Total mass launched stays approximately the same.