This is the second of four questions posed to me by a journalist about open source and the public sector.
I was not involved with the Munich decision at all, so I can only speculate and provide the usual reasons that have been reported about why such failures happen.
First of all, it is nothing unusual if a company or a public government switches products. The particular Linux and LibreOffice implementation in Munich is somehow taken as a representative of all of open source, which is wrong. Munich bought into a particular Linux and LibreOffice and particular companies servicing it and maybe this, taken as a product, did not work as well for them as Microsoft Windows + Office.
Then, as many reports about office software migration show, users are often mentally locked-into Microsoft products. Maybe Microsoft software is what the majority of them uses at home. Maybe it is what they used in prior jobs. Switching to a new software and changing habits often makes people uncomfortable. People who were psychologically invested may have feared the loss of their investment. Reports about resistance to change are legion and range from reluctance to learn to outright sabotage of the undesired product.
It is hard to overcome established habits. It simply needs time for people to accept change, even for something as basic as the software we use in our daily work. One can always try to accelerate this process through training etc. but with an entrenched Microsoft Windows and Office, this will remain an uphill battle for many years to come.