the upstram projects do not ship the slackware/gentoo/fedora/Suse config files (and nobody expects those distros to submit their default config files upstream), so why should you expect Ubunto to do so?
as for their other administrative and config scripts, where do you suggest that they submit them? there is no 'upstream' (other then possibly debian) for them to deal with. they do like every other distro does and provide the source of the scripts with the distro.
If one of the other posters is correct and that for their kernel they are almost completely upstream + backported fixes from upstream, then the main thing that they are doing is tuning the kernel and selecting config options, who do you suggest that they submit these configs to?
where they do have real development work going on I expect them to push things back upstream, if only in self defense (reducing their workload), but it takes people experienced in distro maintenance to really believe that. (just like it takes a experienced developer to really believe in code re-use, and some people never do learn and insist on always re-inventing the wheel)