Yeah, I think that is 90% of it. And the whole related ecosystem aspect. All the major ways of building GUIs suck right now, especially for tiny apps. And to further exacerbate the problem, GUI frameworks are generally tied to their programming languages, Qt is C++, SwiftUI is Swift, Flutter is Dart so on; spewing some terminal escapes to stdout is something that can done from basically any language with relative ease.
A macOS AppKit/Cocoa app uses like 30mb memory and is quite nice to develop or vibe-code. But the whole UX of it is the opposite of a TUI you can run in yet another pane of your terminal emulator next to the other panes you're working in.
GUI apps certainly have their place. But sometimes you want a UX like lazygit where you can launch it in cwd and be done rather than alt-tab to a GUI, open pwd inside it, then alt-tab back to the terminal.