Try turning it over to non-technical people. You will be surprised at how non-intuitive html can be, and what extremely nasty things they will do when they decide to learn just a little bit, ie style attribute hacking galore. If you want dead simple, consistently styled content to be written by non-technical folks, Markdown is much better IMHO.
This is something that can change with a bit of training.
All the "plain text" formatting languages tend to break down. They work until they don't and then somebody invents yet another text-based pseudo-markup language. Asciidoc is best of the worst but fundamentally it's a bad idea. If you're willing to make the investment in tools and training there's a lot of value in enabling people to write real HTML (and MathML) or, better, Docbook + domain-relevant XML that produces real UI-agnostic structured information.
The problem here is that the tools are terrible or expensive or bloated. There's no reason why this should be the case and it's likely a real market opportunity.
Agreed! If I need to debug it in chrome inspector (or similar) I don't like to have to think in terms of the abstraction I'm using to get the result I want.
Web development is complex enough (server side, js, css) without adding an abstraction layer to your markup too.