Yeah there’s more stuff that runs in the shell. But pretty much all the things you mentioned would work on a VT100 from the 70s. This is about modernising the terminal itself.
Hell, Linux terminal emulators don’t even have a “clear screen & scroll-back” keyboard shortcut like Command-K on Mac. There’s no command output history, there are no auto-complete popups, editing commands is still extremely basic (no multiline input for example). The command prompt doesn’t even have the text editing capabilities of Notepad.
It kind of is. For a very long time it was the only option.