I would argue it's a "give a mouse a cookie" situation. On the simplest side of things, stuff like Zenity exists for super-simple GUI dialogues and user input b

I would argue it's a "give a mouse a cookie" situation. On the simplest side of things, stuff like Zenity exists for super-simple GUI dialogues and user input but isn't very customizable. You want a window model with a visually-distinct root window and identifiable dialogues and child processes. You also want async management between those windows, atomic data handling for both processes, signal handling for sending data between them, GPU-accelerated animations... what we really end up wanting is pretty much an entire OS. The best GUI toolkits I've used are either heavily abstracted (tkinter/pygame) or absurdly full-featured (GTK/Qt).