The Economist on the Desktop Linux: Free is too expensive. An interesting reading.
To succeed on the desktop, Linux needs to penetrate the office. Unfortunately, there is no such thing as a single Linux to go up against Windows 7. What there is instead is a fragmented field of hundreds of different Linuxes, each with its own learning curve, skill set and maintenance needs. Even the top five distributions (Linux Mint, Ubuntu, Fedora, openSuSE and Debian) cannot offer a big enough user base to attract adequate support. That is what is wrong with desktop Linux. Hobbyists and enthusiasts may be willing to invest their own time and effort to keep a desktop Linux running. But the corporate world cannot afford such luxuries. In business, the biggest single computing cost is not software licenses, but the salaries of the support staff. And as far as licensing fees are concerned, the biggest single cost by far is not for operating systems but for enterprise applications.
I'm not sure the community around fedora or ubuntu (etc.) is willing to provide support; they surely can't make up the level of support needed by enterprises so I wouldn't blame much the size of the user base.
Desktop Linux, IMHO, should just get easier for desktop users. OSX for example is just simpler.