If 2005 text editors autocomplete made it easy to balance and indent html/xml tags and syntax highlighting like today, would JSON, Yaml, Markdown have taken off? In The Art of Unix Programming from 2003, the author states editing xml by hand is torture, hence we must invent unique text formats and parsers for the same.
I have not been able to configure an editor that makes it less painful. I think it's not just the verbosity (although that is painful) - the prefix notation makes some things inherently hard to read. MathML is almost impossible.