Linux vs Windows result was that the whole question become pointless, desktop computing was replaced by cloud and mobiles. This will be eventually also fate of FaceBook - we might see no direct FB killer, but something completely different which makes whole class of social networks pointless. Maybe telepathic technology - we could barely guess. Btw, same thing will happen with Google as search engine - generic web search is already less and less relevant, as we do not have "homepages" anymore, relevant stuff is consolidated to few portals which have better direct search. This does not mean that the corporates disappear - if they are well run then they just adopt to new areas.