Example: Linux in schools.
1. Teachers don't know much about linux
2. Computers aren't fast enough to work with GNOME (which is default in most packages they install)
3. Kids don't get it. Open office is the only familiar-looking application there.
4. They won't be able to apply their skills anywhere
add: 5. Microsoft makes some generous discounts. Simply because something is worth more than nothing. Piracy is very widespread here (this part is changing on corporate level, though).