Heh you're quite funny. You do realize that by making it's own Office versions incompatible MS would create the same exact trouble to all its own existing user base as it would to OOO users? Only difference would be that OOO users would get the update free of charge and all MO users would probably have to pay for it. So no, that kind of game would shoot them into their own leg bigtime. They're already fighting hard to find justification for the price of MO. Corporate America may move slowly, business directors usually do not understand IT at all and this affects the decision making. If the management is buttered by MS of course they'll stick to MO. If they consult their IT professionals they might turn not only to OOO but linux 
Just out of curiosity, what's your position in the business at the moment?
IT director for a proprietary trading firm. We are using both Linux and Windows as the reasons to pick systems is not our feelings towards one company or another, but what they are best at. You?
What you stated above is naive. MS has that problem now. Older versions don;t read the new formats. Latest versions read all, so all you would have to do is keep up with the patches. And no, MS would not charge you if that was the game they wanted to play. Don;t forget, this is all under the assumption that MS wanted to take out OO using this method. They can take them out legally also. I ll ask you again, how painful is it to apply patches from HT? You think a company like MS could not accomplish that? What if they start encoding the file formats? Sure OO will catch up eventualy but after how long?
How legal would that be? Do I want to deal with all this as a company? Or is it going to be free like Linux? (I think our bills are pretty hefty for that "free" os).
In either case, we have so many other things to worry about here that a move from MS to OO would not only be a waste of time but I would fire my self for even thinking about that

What exactly does it accomplish or fix? I have no complains from anyone about MO or they just don;t tell me lol.
Let me know when Bank of America or the CME or some other big company switches to OO

BTW, do you do web development by any chance?