Microsoft already had an OpenDoc style technology called OLE. It really wasn't that great, as a technology it had some serious flaws. Read the Wikipedia page, it is quite enlightening.
I actually remember using an OpenDoc application for a short while, it wasn't all that.
OLE was primitive compared to OpenDoc, or at least the direction it was going. Apple had a similar technology called Publish and Subscribe. I sat though a hands-on demonstration of OpenDoc at a MacWorld Expo many years ago. Obviously it still needed a lot of work, but the potential was there.