* A lot of software used by them is certainly Windows only (they will have to find alternatives, change their workflows or invest in some windows virtual machines)
* Windows tooling for organizations is much more mature. There's a reason virtually everyone uses AD.
* Linux is very focused on user freedoms. This is not usually important in the office. But freedom to configure things is a freedom to break thinks, and cause admin headache.
The problems are solvable, but it doesn't mean they don't exist.
Oh and I love nixos, and I always wonder how realistic would it be to use it in a company for management of thousands of desktop machines. Sounds like it would be perfect for it, but i don't know any stories.
The reason everyone uses AD is that you can have a functional Linux client in AD. But you cannot have a Windows client in any Linux-based LDAP+Kerberos setup.
The problem isn't that there isn't a good solution for Linux in big organisations, the problem is that Windows is only compatible with AD, nothing else, so the more compatible system (Linux) gets shoved into AD.
It's not very different from Bavaria or neighbouring areas such as Jylland or Lower Saxony: https://en.wikipedia.org/wiki/List_of_German_states_by_house...
I think transitioning to a different platform is mostly an organizational and political, rather than technical problem, and the main roadblock is educating users and altering processes to migrate away from MS Office.
That said, modern Linux distributions like NixOS or Guix could be great to manage large fleets of computers, keep them up-to-date, and upgrade things without fear. In my experience, that is the main technical issue administrations are experiencing.
And of course, running free software is great because it brings freedom to change things.