Here's one example: Why can't I interact with text at the prompt in the way I do in every other text input context on my modern computer? Selecting text with shift and arrow keys, moving the cursor with the mouse.

Keep in mind that I do not deeply understand the stack of standards and implementations that comprise a terminal. That said, my assumption is that this complaint is an unfortunate, unavoidable byproduct of that stack.

While introducing newcomers to terminal usage, there are simple actions from the gui world that do not work at all, or even seem to break the terminal display. It's extremely confusing for them, they get over it eventually, and come to accept that the terminal just can't do certain things. This is what I mean by being unable to move into the future.

As a point of comparison, consider how much of a mess it is to deal with spaces in file names, in bash. To a newcomer, this seems like a crazy hassle, some antiquated nonsense. It's hard for them to understand how experienced Linux users can stand to deal with it. It's annoying, but it's a direct consequence of the choice to use the space character as the delimiter between tokens in bash. This choice is actually super convenient most of the time, because that is the best use of the space character/key in a terse shell language.

What is the analogous rationale behind the shortcomings of the terminal paradigm? What would we need to give up, in order to make the terminal interface a little bit more modern?