Maybe ten years ago I would have said that, but these days it seems they are typing their "documents" into an email composer or a website form (be it a frontend for blogger, wiki, wordpress, etc).
You mustn't work in an office environment then. The only significant break from MS products I've seen has been Lotus Notes... which was significantly worse than Exchange.
MS Office is the defacto file format for office work, and MS Office on non-Windows platforms (ie. Mac) is so bad as to appear intentionally crippled.
I work for an decent sized international company that not only has a presence on the web it also has factories and all of the complexities that go with that. I would indeed count where I work as an "office environment", I even have the cube, office badge and mailbox to prove it :)
MS Office is the defacto file format for office work, and MS Office on non-Windows platforms (ie. Mac) is so bad as to appear intentionally crippled.