The SIF is to supplement the physical structure, it doesn't replace it... A ship doesn't fold in on it's self under the stress if they turn off the powerHigh impulse speeds, and extremelly high warp speeds cause huge stresses on the ship, and in the case of warp speeds, shearing differentials, which create a whole other problem (the ship being squashed and squished in directions other than along it's mass lines, from the impulse engines!)
Technically a completely cubic spaceship would look horrific from a wiring diagram point of view, because there's no place to put an obvious backplane to spur everything off. Starships the size of small towns are never going to have a simplified 'wiring diagram' because of the sheer logistics of moving consumables, power, life support and people round the thing. Having those things mounted in or next to the corridors made a lot of sense in Trek, as you have to be able to get to them if they have a problem!
Beyond that I agree with TonyG about the whole redundancy thing, all those things crossing and overlapping is going to look rather messy in a wiring diagram. However your house, exposed, with all its wiring and plumbing showing would look bad, as would it's wiring diagram, but in reality you don't hardly see it, as in the shows![]()