they do though, just not in the way you think; in general chimera is designed so that whatever you install from the repositories, it'll yield a working out of the box configuration

you want a desktop? you install it and it works; there is no (mandatory) tinkering with getting dbus, audio, wifi/bluetooth, or whatever else to work - most importantly things are set up in a way that installs are consistently deterministic and auditable (there is no reliance on complicated shell hooks or anything of the sort to do any kind of "fixups", most packages consist solely of extraction)

sure, when you involve third party shell scripts or whatever, there is a chance you'll run into compatibility troubles, but perhaps not as often as you think either