WIFI is not reliant on the GUI.
NetworkManager OTOH always was “reliant” on the gui more or less.
Again, there’s a text mode tool to connect/disconnect (lacks other features like actually creating a connection though), and a system connection gets established automatically during boot without entering a GUI or even login.
You need to have a wider perspective when developing software, you can just say well if you use wifi you have a system tray because you must be using a desktop. This is sublimely short sighted.
That’s similar to complaining that you cannot use Firefox in text mode.
NetworkManager is designed to make a user’s life easier that uses one of the graphical desktops. There’s no limitation to having to have a system tray or a GUI at all, somebody would just have to write a frontend that supports that. Maybe one even exists, I don’t know.
And you’re wrong that you have to have a system tray or a GUI to use wifi, even when you do use NetworkManager.
You can disable NetworkManager and use Wicked as well, then you can (and have to) use YaST for configuring it as I already told you as well. You could of course just edit the text config files that YaST changes if you know what you are doing.
And it should just work. It did in previous versions with ifup.
There might be bugs/problems in wicked regarding wifi though, I read about some I think, but I haven’t tried myself. (I’m happily using KDE and NetworkManager anyway)
And there are other alternatives, like WiCD.
You can use it in text mode? 