Well you can have that, those are the repositories mostly, which you have access to when building your linux. So you have a mature source of code, but what makes a distro 'mature' isn't really of any value in the embedded space. Kernel, core utils, init system, some packages and you custom code, and your done. You now have your own distro, code is mature, boots really fast and is probably more stable and secure that the mature distro which is trying to be everything under the sun. When you only need the linux to do one specific thing you can make something that is really rock solid and actually have a sense of everything that is going on under the hood. Having some guy whose, honestly mostly uneducated, solution is to just throw fedora on there is going to create a crap system.