For some reason email is singled out as a problem to fix, and profit from. Word processing and spreadsheets are equally broken, very few people actually know how to use Word or Excel to any meaningful proficiency.

I don't buy that email is broken, not anymore than other communication means at least. The clients may be too hard to use or too limited in functionality. The sad truth is that beyond a few walled of webmail solutions, like Gmail or Yahoo, development of email clients have stalled. Add to that companies that spend zero effort in education staff in using Outlook (because let's face it, we're talking about Outlook for the most part, when talking work emails).