I just upvoted mmeier for the first time ever, 'cause he's _right_ (this time...). The problem for those who would be Tuxers is, and always has been, applications. John User does not CARE what OS is in use. He simply doesn't. He only cares if the software available can do what he wants/needs to do. if it can, he does not CARE that it's evil closed-source, locked in, capitalistic software instead of pure, open-source, standards-based software. he just wants his damn spreadsheet to display and print properly. He just wants his email to arrive on time, his calendars to be updated properly, his reports to show what he wants. Linux could be all-singing, all-dancing, but if it won't support software which does what the users want it won't be used.
And, no, 'educating the users on the alternatives' won't work. That means that either the company or government or whatever has to spend time (and money!) training staff or the staff has to learn the new way on their own time (and dime). And, in many cases, the 'alternatives' simply aren't good enough. The GIMP is a wonderful tool, for what it does; it's not Photoshop and never will be. For certain jobs you simply have to have Photoshop, nothing else will do. (Of course, there ain't nothing which says that you have to have a _new_ version of Photoshop, so far Photoshop 5.5 has done everything I've needed it to do and I see no reason whatsoever to go near Adobe Clutch of Crap.) Thunderbird does some things nicely, other things not so nicely and other things not at all. Outlook may not be the best mail software in the world (now there's an understatement) but it can do things that Thunderbird won't even try. If you don't need those things, you can use Thunderbird and never miss anything. If you need those things, you simply can't use Thunderbird. Period.
One of the reasons why we don't use Apple iWork around here is _precisely_ that Apple doesn't support stuff for any extended period. (They not-so-recently dropped the disaster that is Pages 5 onto an unsuspecting world; if Microsoft had done what they did, then MS would have been lynched, and rightly so. I personally have a whole lot of old Pages '09 documents on my home Macs; they've being converted to DOCX format, not because I love Microsoft, but because DOCX is likely to still be supported ten years from now, while Pages '09 is dead, dead, dead. And, sorry, Open Office and Neo Office and Libre Office simply don't do what I want, what I need. Pages '09 did. Word 2010 and even (ick) Word 2013 do. Word 5 does not. Yes, I tried them. No, they don't do what I want. No, I'm not about to fork Open/Neo/Libre Office myself. Why should I, when Office 2010 and Office 2011 do what I want?) A lot of Tuxers do NOT understand that most people simply don't care about the OS, they care about the job. If Open/Neo/Libre Office could do what I want, I'd be converting my Pages '09 files to ODT, not DOCX. They can't do the job. LibreOffice 4.3 on a Mac cannot properly import a Pages '09 document. It just can't. That means that I'd have to export my documents from Pages to a format that LibreOffice _can_ handle. Pages '09 can export to some formats LibreOffice is familiar with... and which Word can read, too. And Word actually has certain features, particularly with regard to styles, that I want and LibreOffice doesn't have. Still. Word's had them since the 1980s. I've been using them for over 20 years. I like them. I really don't care if current thinking has them classified as old and stodgy and not worthy of being added to nice new modern software.
But, hey... carry on.