Most of the US government is on M365.

And the only reason they achieved a FedRAMP ATO is because most of the government was already on it. The platform is a piece of shit.

What's the alternative for large multi-national organisations?

Probably different open source projects + doing things in-house. Which--I would assume--would likely cause much more frequent and longer outages.

Cloud email as reached the utility status like electricity, it's not economically justified to run your own unless you have a very specific use case.

That's right. I don't think most people should

Active Directory, Sharepoint alongside Office, anyone involved in game development related to PC and consoles (all devkits use VS plugins) and Valve has failed to bring native games into SteamDeck, existing .NET enterprise applications, Typescript, Github, VSCode, node,...

> Active Directory

This is big for medium/large fleets: fairly good central authentication, as well as being able to set policies for machine management (GPO).

I've also heard good things about PowerShell.

>> I've also heard good things about PowerShell.

That is despite Microsoft ...you do know they tried to fire the guy who created it?

The decisions on which stack to use made by business people despite the objections from IT. I’ve seen this pattern so many times across various organizations

It's not up to the IT department. Network effects means if you don't use MS you cannot interperate with other MS-based companies as well. So you need at least some MS integration and they are happy to sell you the rest of the stack bundled with it.

There is also another type of network effect: hiring candidates or contractors with knowledge of the MS stack is much easier than finding someone who can set up an alternative.