Just how much of a saving is there really to be made by the supplier/manufacturer by including a bare-minimum 2 pair patch cable with a router instead of a standard CAT5e?
I'd say there is actually an argument in favour of reducing the number of cores to the bare minimum, as each additional (unused) pair increases the metallic surface area that is exposed to noise pickup, and that noise can then be coupled into the other conductors, thereby increasing the noise they already carry.
Given this money scrimping on accessories, it encourages me further to try to run my modem from a 12v battery to compare the performance when running on the supplied 12v switch mode PSU that's quite noisy on an AM radio.
On a slightly related note, one thing I like about the Netgear routers (such as DG834GT) is the power brick, judged from size and weight, seems to contain a big, heavy, old fashioned transformer. In contrast, the smaller, lighter bricks that power some other routers are obviously 240V to 12V switch-mode supplies which, I always suspect, are more likely to emit unhelpful switching noise.