Labor is expensive, materials are cheap. Cable lacing doesn't protect the wire from abrasion like wire loom does. For bigger bundles of wires there's also the

Labor is expensive, materials are cheap. Cable lacing doesn't protect the wire from abrasion like wire loom does. For bigger bundles of wires there's also the "plasic flow" (basically the weight of the bundle causing the cable to cut the insulation) issue another commentor mentioned that loom is basically immune to.