It simply never occured to me Microsoft would make their office format suck on purpose. Bill Gates writes in that e-mail:
One thing we have got to change in our strategy — allowing Office documents to be rendered very well by other peoples browsers is one of the most destructive things we could do to the company.
We have to stop putting any effort into this and make sure that Office documents very well depends on PROPRIETARY IE capabilities.
(There’s a lot of other interesting e-mails in that directory, for what it’s worth.)