Could you please stop posting unsubstantive comments? You've been doing it a lot and it's not what this site is supposed to be for.

https://news.ycombinator.com/newsguidelines.html

I was wanting to compare the industrial scale cost of doubling the width of a pizza to doubling the width of the cross section of a starship. Your entitled to you're opinion

No, much higher, because of extra engines and more plumbing.

Starship is already pretty marginal of an upper stage and it's fired early. More marginal than old Space Shuttle, but cheaper to refurbish.

OTOH, the weight of the rocket grows mostly linearly (it's essentially a skin around propellants), the number of engines grows with the square of the diameter and the fuel volume grows at a cubic rate, so the engines can burn for longer (at some point, aerospike engines will become practical).