A water large water pipe has the potential for more water to flow through it, but if a smaller pipe has adequate capacity to carry all of the available water then having a larger pipe wouldn't result in a benefit, but would have more potential.True, but you need to take this a step further. If you are listening to test tones, no problem, however a bass drum requires an instantaneous burst of current in a fraction of a second. Obviously, having that larger pipe will deliver more water in that fraction of a second than the smaller one. Also, the multiple connections prior to your system outlet will limit the potential for that instantaneous demand. No doubt that dedicated lines will improve bass definition, but other aspects of the sound will improve as well.
I have encouraged many local friends with quality audio gear to install dedicated lines and told them if they didn't think the improvement was worth what they spent, I would pay their bill. All have thanked me, and some said they wish they had not waited so long to do it.