I'd also love if maui actually takes off since it does seem pretty neat, but until microsoft uses it for teams or any other of their clients, I'll pass.
They also aren't even targeting linux or web browsers, which doesn't really make this more compelling than Flutter.
https://dotnet.microsoft.com/en-us/platform/customers
Teams was originally written before this particular release existed.
They were talking about Microsoft constantly re-inventing GUI frameworks and then abandoning them. For example, you bring up Teams, but Teams is actually an Electron app, which gets to the point of the commenter.
It's insane because actually all anyone wants is Windows Forms and WPF. If Microsoft made a cross-platform version of Windows Forms and WPF, they would be the cross-platform frameworks, at least for desktop.
I do wonder sometimes whether MS should just pick it up as a default-endorsed desktop UI toolkit for .NET, but I guess rivalries, internal turf wars and other priorities make that difficult.
https://github.com/dotnet/maui
.NET is Open Source
https://dotnet.microsoft.com/en-us/platform/open-source
I do share your skepticism of Microsoft, but it looks like the economics and cash flow dynamics have changed drastically after the advent of the cloud.
Microsoft is more focused on getting developers onto its ecosystem and help them with open source projects with the hope that they will use its Azure cloud services and bring in the money.
My skepticism is a bit relaxed now and I have no qualms using .NET.
I hope I am not wrong.