I love Linux and use it instead because its better than Microsoft for the places I use it or Open Source products like Libreoffice because I dont have 2K to spend on Microsoft Office not because of the reasons you mention, to do so would be childish. ...
Since MS software has sort of become the norm in businesses, most students etc. will spend money on acquiring software they want to become accustomed to and hence they aren't exposed to alternative software. If only businesses where aware that they could easily build their whole infrastructure on FOSS that is in my opinion better in some instances than the proprietary counterpart.
The biggest motivational point to me is Linux is scalable, normally the default out of the box configuration is sufficient, but a sysadmin can control every aspect of the system, whereas MS systems enforce "best use policies" that does not always apply to all business entities. Not to mention forking out thousands for CAL's.
Incidentally our company is after being in business for 30 years and running MS for 20 years, slowly undergoing a paradigm shift to phase out MS as far as possible.