They say that their 21000 pc pilot project with LibreOffice shows that using LibreOffice over their proprietary office tools increases the cost by 70%. This seems very difficult to believe without proper arguments.
* How many users do they have, what's their sophistication level, and what kind of retraining will be required to use a new software product?
* How will incompatibilities be handled with their existing documents? Is LibreOffice absolutely 100% feature complete identical to Microsoft Office? If not, what proportion of documents use incompatible features? How much effort is required to determine this incompatibility? How much effort is required to redo these documents to fix the incompatibility? How many employees are required to be on such a conversion team and how long will the conversion take? Can the conversion even be done?
* How is interaction done with external users who send Office documents? What happens when users outside their office send them Office documents which make use of incompatible features? Will this require maintaining an ongoing conversion team? What is the opportunity cost inherent in the delays in getting documents converted?
* How is installation of LibreOffice done? Can it be setup on a centralized WSUS server and automatically deployed to every user as Microsoft Office can, or does it require an army of people manually installing it on thousands of PCs? How are updates for both version upgrades and security patches handled? What is the typical update schedule for LibreOffice (security-related patches, compatibility upgrades, etc.) and will this need to be done manually as well? How many man-hours per year will this take?
* LibreOffice doesn't include an email product. What alternate solution would they use? What is the cost to convert all Outlook email and archives to this new solution? Can the new solution make use of all calendaring and other Exchange-related features that Outlook has? Can the new solution be deployed on WSUS and kept up to date automatically, or does this too require an army of people manually installing and doing updates? Can they maintain the security permissions they currently use, such as restricting the ability for users to forward internal communications outside the office?
* LibreOffice doesn't have a Visio, Project, or OneNote replacements. What are they going to use for these? How do they convert existing documents and interact with external users who send them Office documents? Is it even possible?
And so on and so forth. Free is seldom free, and LibreOffice isn't a replacement for the full suite of Office functionality. People like to bash Microsoft because it's what all the cool kids are doing, but once you factor in the amount of time involved in all the above Microsoft Office is the cheapest solution around.
A lot of migration projects seem set up to fail, the quickest way to do that is make the users unhappy and site increased support costs.
In terms of single documents used for correspondence, they likely need things like mail merge, change tracking, multiple authorship (housing departments deal with a lot of legal issues, from evictions to liability to real estate transfer) and so on.
You're falling into a classic developer trap of not being interested in other people's jobs, and thus assuming that the jobs don't need uch int he way of technology. It's the same mindset that leads people to suggest using emacs for everything -because that's what the developer uses all day; or doing everything at a shell prompt - despite the obvious market preference for GUIs; or that everybody should learn to code - though most people clearly prefer not to. One might as well suggest that developers should just stop piddling about with software and learn to build their own hardware instead of pursuing the massively wasteful path of general-purpose computing.
A lot of my time is dealing with reports and projects where somebody decided that they didn't quite like how a title of a table was formatted and so made their own "fixes" which looked ok on their machine. Or they couldn't understand some remote object linking functionality so they converted the spreadsheet into an image and embedded that.
I suspect a lot of companies, and certainly most goverment offices, would be more efficient if the people who write pretty much standard letters to customers/claimants didn't have the same MS-office install as somebody editing 10,000 page technical reports for an Airbus A380.
You can (or at least we used to) customize the menus/toolbars for Word to make a simplified version for secretaries that were really happier with typewriters.
LibreOffice has mathematical formula editing that I find much more congenial than that currently provided in MS Office 2010. (Yes I know LaTex but I'm talking casual use of simple formulas here).
If you already own office then the cost of getting new calandering and email software up and running for a large group and then training them on how to use it is non trivial.