I wonder about that. I'm probably not thinking of some very important things. Edge, Office, Active Directory, Co-Pilot, a Windows DE, userland programs(could even be GNU+Windows, don't want to forget notepad and minesweeper), Powershell, DirectX and SDKs. I think they could do it in a year or two. I just figure, if they could improve Windows in the cloud, they would have done it. And they've already got a massive head start with Azure Linux.