Word is light-years ahead of any open source alternative. Gimp is not a photoshop replacement. These guys don't care about Apache on their desktops. :)
I generally don't require any better than Markdown and for larger documents I just LaTeX.
However I am normally sent work documents with all sorts of macros from other companies (embedded forms) to fill out for things like payments, right to work etc. These require Microsoft Office. Originally when I started I thought I could get away with Libre Office. It worked at best 50% and these weren't complex macros (I inspected them myself).
None of these forms are outside the norm of what a HR department, University faculty office or most medium to large companies use.
The reason is mostly security: nobody wants to run random macros on their machines (where nobody means their IT departments, the users wouldn't care) and for the uses that you mention, for random forms, web-based forms are used and links to them are getting send.
At least in my corner of woods.
Now if you say Excel, however, we might start to agree.
BTW, while Gimp is not a photoshop replacement (please fix the window behaviour, guys) but krita is getting really nice, and plenty good enough for your average corporate user.
If you mean the multi-window behaviour, as of 2.10 the default is now set to single-window.
If you don't have 2.10 in your distro yet, you can toggle that on in the menubar: Windows -> Single-Window Mode
I'm not sure which government departments are using Photoshop but the few that do could just as easily use Macs.