> The right answer here is if the situation is that bad, make a very public long-term commitment to shift to something else & up-level your IT department to be able to execute multi-year projects competently.
The problem is that there isn't much in terms of alternatives, especially not if you prefer to have one software / vendor / tech stack.
- In groupware, there used to be Lotus Notes, but that went down the drain years ago. Thunderbird can do everything Outlook can (i.e. provide an email client, calendar and address book), but there is no official(ly supported) Thunderbird server software suite so there's always a potential for subtle bugs between whatever one chooses for directory, email and calendar backends.
- for AD there's obviously Samba but it, again, lacks a management UI that supports all of its features, so yet another potential for issues.
- the Office suite alternatives are even more of a nightmare, both in terms of usability, stability as well as compatibility with the millions of legacy files originating from Office. Or hell, even compatibility with old versions of the same app isn't a given in LibreOffice. (And I'm not sure stuff like MS Access even has a FOSS counterpart)
- And then, there's all the other stuff that integrates with AD for authentication/authorization. In a lot of cases, it's "either use MS AD or you're on your own when you hit issues".
- finally, Windows itself. Essentially, the US Government would have to sink billions of dollars into ReactOS development to make it compatible enough with mainstream Windows versions to run all the legacy software that people use - and no, WINE alone is not enough, not for anything that deals with hardware directly. And I wouldn't assume it's possible to even hire enough developers that are skilled to develop for WINE/ReactOS and fulfill the project requirements of never having been exposed to Windows source code.
Microsoft has achieved an insane amount of vendor lock-in, even Apple with all its financial and technological might or Valve (who invested a huge amount of money and work into getting WINE feature-rich enough to run a ton of AAA games on their Steam Deck) have been able to even come close. They can provide as shitty a service/software as they want, their audience literally has no other choice.
(Me personally, I'll keep my Windows 7 and 10 VMs alive for as long as I can, but no way in hell I'm ever moving to the ad-ridden, bling-bling flashy pseudo-hipster-UI disaster that is Windows 11)