Sure, but why are we using the lowest common denominator, plain text, and then adding formatting? Why don't we start with something like a visual HTML or DocBo

Sure, but why are we using the lowest common denominator, plain text, and then adding formatting? Why don't we start with something like a visual HTML or DocBook editor, and then apply parsers to generate plain text, PDFs, etc? Is it because we as programmers live in a plain text environment and are happy with the status quo, or is it because the tools aren't good enough?