So I haven't seen big Orgs switching to Libre/OpenOffice - since they have the resources necessary for whatever licensing and because they get special deals too and because MS Office is a lot better than Libre/OpenOffice, then they have no real reason to switch.
However, the big problem Microsoft faces is that one reason Office is popular is because of piracy, which is like this freakishly big elephant in the room. I can bet that most home users that use Office do not have a license for it - I've seen this happening with small to medium businesses too in my country at least.
And for a small to medium business, what makes more sense? Shelling out the cash for Office licenses or going with a completely free and legal alternative? Considering most such businesses don't actually need Exchange integration or other niceties that MS Office provides, the choice is pretty obvious under the threat of being caught.
And this is the big problem for MS Office - it's an awesome software package, but judging relatively to its upfront cost to home users or small/medium businesses? Well, the extra value provided starts to fade in comparison to a $0 price tag.
