As with every large Microsoft migration, the problem isn't figuring out what's necessary to run a government.
People in high places only know Microsoft and they don't want to risk having to learn something new. National security isn't as big of a deal as having to spend a few afternoons of training, after all.
People in high places have assistants to operate Word for them. If anything, the money Microsoft pours into lobbying is a bigger threat to gaining independence - the killing of the LiMux project[0] made that quite obvious.
I don't disagree but the world then and the world now are different places and people pushing for less of a dependency on american tech companies have a real chance to make some headway with The Orange One(TM) sitting on his throne over the pond and Microsoft seemingly determined to make themselves (more) unpopular with techies generally not entirely sure what they are doing with Windows 11 but after 3 decades of running a microsoft OS I don't have one in the house (in fairness windows hung in for gaming for the last 20 odd years, I've been linux for everything else since the millenium).
People in high places only know Microsoft and they don't want to risk having to learn something new. National security isn't as big of a deal as having to spend a few afternoons of training, after all.