I was making the point that surviving without something in the past or currently is no reason not to improve it.

Improvements are awesome! That’s why I linked to the text/enriched RFC. I really wonder if anyone who downvoted actually read it, or just emotionally reacted.

I don’t think that HTML emails are really an improvement: full-fledged HTML engines bring in too many opportunities for exploits and privacy loss. They definitely add capability, but at too high a cost IMHO.

In general, I think that our industry would benefit from asking ‘can we?’ less and instead asking ‘ought we?’ more.

Can't argue with your final point at all.

However, my thread is more "can we do it differently?" instead of "maybe we shouldn't do it at all"

I agree, HTML isn't right for email.

Some different approach, possibly a markdown variant, with decent style support (basic css like background colours, fonts, like markdown themes in a code editor), why not explore that.

There's no reason emails need to be plain. RTF is a horrible format, markdown is much more prevalent and easy to make a simple UI formatter that obeys the standard for non technical users.