There are a number of factors at play here: 1. Preinstallation (Linux does not have deals with major manufacturers so they are not generally installed by default on computers or even a choice when purchasing) 2. Familiarity (People use what they're used to don't like to migrate) 3. Software incompatibility (Some software will not run on Linux; this software might be highly desired or necessary for the users) 4. Perceived difficulty (Linux has origins in the programmer/hobbyist communities and the misconception that installing/running linux is difficult persists) 5. Lack of support (unless you are using an enterprise Linux [ex RHEL], there is no official corporate support. Trouble shooting must be done via wikis, forums, mailing lists etc.)