Comment by II2II

You pretty much need to use markup (or control codes) for rich text. Take bold, italic, underline, strikeout: those four can, and are, used in nearly any combination. You would need one bit for each of them. You would need two bits to specify four levels of headings. If you don't allow for that, you are back to using markup. You would also need one bit to specify proportional/fixed width font, because that is a thing too. That remaining bit would have to be used for superscript, since superscripts are commonly used for footnotes and simple mathematical expressions.

Okay, you can now create passable rich text documents for a limited (though common) range of purposes with that 8/24-bit breakdown that was suggested. But you may have noticed the author mentioned subscripts, which wasn't in my list. Well, it turns out that subscript and superscript have a terribly limited range of applications if you are specifying them per character: x^2^2 would be visually identical to x^22, and x^a_b would look different from x_b^a (with both presentations being nonsensical). The use of subscripts and superscripts in any technical applications would be severely limited. You need a much richer markup language to be truly expressive. So there really isn't much of a point in offering subscripts. Superscripts, sure, because they have a few non-technical uses.

Yet the reality is that people want a much richer set of formatting options. At a minimum, they want to select fonts and font sizes. Some of the formatting options have semantics. I know I crammed four levels of headings in those eight bits, but that only makes sense in headings. It doesn't make sense to specify it per character. Then there are other common document elements, like tables. You can create decent tables using monospaced fonts, but that is limiting and would produce undesirable results in some cases (try displaying April 5^th sensibly, using a monospace font so that it won't affect the width of the columns). On top of that, you are ditching the concept of styles because that implies some sort of markup.