Easy. Intertia and incompetence. Government is full of paper pushers who hav eno higher wish but to live comfortably on tax payers money until they retire. The key to survival is to do what everyone else is doing, and not to be the first to try anything new.

The good thing is, as soon as someone tries anything new, and it looks like it is a success, the paper pushers will join in as soon as they think it is safe, and try to steal the fame and glory.

This is just how the government and the public sector works.

Not exactly governments, but I work with NGOs in Germany, and plenty of them use Teams and other MS products, just because they receive them for free and don't have the budget to pay someone to install open source alternatives. Training is especially costly and in these environments people are not really "digital native". It's not even about age, but about culture: people here will do what they are trained to do and fear doing something they don't know, because they might "do something wrong". I was responsible for a platform that gives free online storage, chat functions and videocalls (BBB) for NGOs, and had to hear these arguments over and over when discussing migrations. So unless there is a political drive, together with good trainings and support, the transition is very very difficult.

The big problem, and I say this as someone that appreciates some of the Microsoft technologies, is that it is always first and foremost about Office, and nothing else.

Forgotten are Windows, XBox, DirectX, VC++, C#, F#, TypeScript, Github, VSCode, Azure, Teams, SQL Server, SharePoint, Dynamics,....

Ah but some of those are FOSS, they are, pity that most money and project steering only flows from one place.

Repeat the same listing exercise for every US big tech company and their influence on the computing industry at large, and possible geopolitcs, that is how we end up with HarmonyOS NEXT with ArkTS.