Almost everyone I know who's been exposed to (and intrigued by) a friend's/acquaintance's Linux installation has been stopped by a fear of weak Office support. Aside from the hassle of partitioning and installing Linux on a Windows computer, this seems to be the single issue keeping them from switching. I'm not pretending that this anecdotal data supports a blanket statement that it is the main issue keeping people from Linux, but it certainly helps belie your blanket statement that people who would switch to Linux are relatively unaffected in that decision by Office availability.