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.
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.
WezTerm [1] is probably the best example right now but there are others.
These aren’t your father’s terminals.
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.
Complete madness and inefficiency.