As you suggest, this is definately a legacy issue of being tied to the teat of a 1980's terminal. People still like to edit in simple editors.
I've viewed it as a Model-View-Controller problem, where everyone is attempting to merge the Model and View into one. Technically your editor should be worrying about the View. It can draw division however you configure it to. But when saving to a Model source file, that should be portable, without any (or very little) formatting embedded in it (e.g. MultiMarkdown).
You should be able to customize your editor, much like swapping out a CSS file on a website, and skin it to your desires.
We talked about exactly this at a Camp Smalltalk almost a decade ago. If it had flown, at least one computer language (Smalltalk) could've allowed each programmer to have their own customized code formatting (View) while the code was actually stored as the Abstract Syntax Tree nodes.
I've viewed it as a Model-View-Controller problem, where everyone is attempting to merge the Model and View into one. Technically your editor should be worrying about the View. It can draw division however you configure it to. But when saving to a Model source file, that should be portable, without any (or very little) formatting embedded in it (e.g. MultiMarkdown).
You should be able to customize your editor, much like swapping out a CSS file on a website, and skin it to your desires.