Stuff gets forwarded around, attached to various systems, etc. Having the entire thread, unmodified, has been a lifesaver for me more times than I can remember.
Having the entire thread is also a major PITA most of the time it's included.
With a threaded mail client, if it's necessary to send the entire thread to someone, I can select "Attach mail" -> Tag the entire thread -> and forward it as a MIME-attached mbox.
If the recipient has, say, a powerful, thread-capable mail client, they can open the mbox, read it, filter it, search it, expand it, and collapse it in ways that aren't possible with the horribly lossy Microsoft Outlook format.
As I said: it's used extensively. This doesn't mean it works.
Yea, you do. Sadly you've just gone 6 levels over the head of Sandy the PR person. And that's why it's still the default, because it works for everyone.
Don't you dare start putting reality in the way of my geek fantasy!
You've got a point, and throwing mutt at your typical office worker might not go far. Then again, my (very technophobic) father was dealing with mainframe-based "business productivity tools" in the 1980s. Including some (by current standards) very, very clunky email tools.
I'd throw the problem at Apple. I think you'd find that they'd figure out a way to sort out when it made sense for someone to forward an entire thread to someone and handle it that way. Probably, these days, within a Web interface, though possibly through a mail client / app.
