...is buy it and double its marketshare from 1% to 2% of the Office market to be able to claim credible competition. Similar to the $150m "infusion" it made in Apple some years back (which was actually a patent settlement and not a beneficent gesture).
Unix and X are already largely native on MS Windows. Cygwin ports allow execution of many GNU and POSIX utilities. Unix Services for MS Windows NT is the same vibe from the belly of the beast. "Unmanaged" X11 servers allow X11 and MS Windows apps to cohabit the same workspace -- no seperate X windows desktop required (though frankly I prefer full-screen managed X sessions if possible).