[Glanford]

One of the problems with treating terminals like other text input contexts is that they're inherently different and you're going to constantly run into issues when the context switches to displayed text.

For example, you could get a terminal that allows selecting text with keyboard but what happens when a user inevitably wants to or accidentally selects text from the non-input part of the terminal? Should the input part of the terminal and the display part of the terminal be treated differently? In Firefox as I type this I get a nice big input box where I can do multi-line paragraphs but if I start clicking and dragging to select the text in the input box it'll never let me select text from your comment, likewise in reverse, but on a terminal this would be undesirable behaviour for the common pattern of selecting text to copy output for documenting or troubleshooting. Some terminals have plugins or scripts to allow such selection of text but not for input purposes, if you decide to only allow text selection on the input field as a means of improving text input do you just get two such methods of being able to select text? The sane approach might be to allow selecting all text but you'll end up with paper cuts where a user doesn't care about what is going on before the $ but might end up in situations where text is selected far before the $ because of a reverse search gone wrong, etc.

As an aside, terminals/bash do have some form of text-editor like functionality, readline is the usual library involved (man bash, /^readline) and has reasonable support for moving cursor around words, move cursor to character search, deleting/yanking/pasting words, etc. It's not the best text editing interface but for dealing with a single command line it's usually sufficient. There's even a vi-like editing mode (set -o vi) built into bash if you feel like you need a modal editor for a single line but it seems even less intuitive and harder to grok.

https://readline.kablamo.org/emacs.html

https://catonmat.net/bash-emacs-editing-mode-cheat-sheet

https://catonmat.net/bash-vi-editing-mode-cheat-sheet