[munchbunny]

Main bus designs work really well for building one factory to launch a rocket because the resource demands aren't so high that you run into belt scaling problems.

If you're going for one of those crazy ridiculous high output post-endgame factories, the sheer complexity of running 8+ belts of one resource and branching off 2-3 belts at a time, then having to double that to go from 1k SPM to 2k SPM is way too painful. That's why most of the factories you see north of 2k SPM aren't main bus designs (aka well organized monolith), they're modular designs ("microservice" based). I put that in quotes because at those scales the sub-factory for creating a single input resource might be bigger than a whole base used for launching a rocket.

The analogy actually applies really well to software engineering: for a practice that works really well for 99% of the players (main bus), at a certain level of scale the approach breaks down, and you need a different approach to deal with scaling past that point.

As evidence for that, I usually use a main bus design to get to the endgame, but once I start the megabase scale climb, I break the factory out into discrete, networked (by train) modules in order to keep the resource distribution problem under control.