Your terminal application is an emulator of a decades old technology originally used in physical consoles, with layers upon layers of enhancements that add support for colors, cursor control, etc. At it's core, it's just a grid of characters. The GUI as a platform is quite literally a superset of the terminal, for example because the terminal emulator app is a GUI itself. Hacking the grid of characters to render lines as if it was a GUI is hardly "superior".
I say all that as an avid neovim user myself by the way. On mac/linux I use it through the terminal, on Windows I use it through the QT application.
The new generation of terminals are nothing like what you’re describing: GPU acceleration, full color support, font shaping, support for ligatures, built-in support for multiplexing, SSH and more.
WezTerm [1] is probably the best example right now but there are others.
Of course they are. Your new generation terminals still use decade old protocols, using the same escape sequences to control the cursor position, colors etc.
The "lines" and other UI elements you see in those next generation terminals when you run TUI apps like neovim are still simple characters aligned next to each other to look like a line etc.
Stuff like GPU acceleration is only another layer which was put on top of all of that. At the core they're still using the same old technology.
OTOH it's already probably a couple decades since some more fresh terminal emulator projects have popped up that kick a bit into the old cruft and provide both lightweight stuff and actual drawing routines for specific stuff. From a graphics dev pov it's not nonsense to decide for rendering on a grid, even for UI, i see it a bit like voxel 3D engines.
So i'm really not sure the "layers upon layers" critique is well suited for terminals, in comparison with say some qt/gtk/electron/<your gui>. Also GP is mentioning emacs, which is mostly the same old cruft as a terminal emulator.
I say all that as an avid neovim user myself by the way. On mac/linux I use it through the terminal, on Windows I use it through the QT application.