For a normal person that might be that simple. The issue is that there are a lot of add-ins and integrations of other software into Microsoft Office. That can not be easily replaced. You have to keep in mind that there are a lot of highly specialized programs running in governments and they probably do not offer the same sort of office integration. Also large organizations need administrated their entire backend. That is why most projects in replacing Microsoft Office use the LibreOffice Online version. That unfortunately lacks features. Nothing too bad for normal users, but a admin backend for organizations is just something a single user never uses.

That is to say, it is actually quite hard to switch. Obviously not impossible, but far from “Just use LibreOffice”