I think the "techies" that you are referring to just see the issues with html email that the non-techies don't notice. Some of course just want things to be more like the 80-column monochrome that you mention, but for most it's not that extreme.

I think HTML is way too complicated for email, and it would have been much better if they'd standardised on a version of markdown.

That ship has sailed though, so we're stuck between using HTML or plain text.