Haunted by ancient history

One of the issues here is that *someone* has to remember the values set. It's either in user space of kernel space. If the kernel remembers it, then anyone can query the kernel APIs to figure out what the current wireless settings that have been told to hardware are. If it's in user space, I can imagine someone writing another dbus API for wireless connections, and adding a permanent daemon to keep track of the info.

Historical unix style favors the former, so the kernel services user processes by keeping track of important state for them, because the processes themselves are short-lived and can't do it. Modern unix style is about running everything imaginable in separate daemons. Anyway, someone can just go ahead and define the dbus API for wpa_supplicant or something, and then tell everyone to implement that.