You're thinking of old Microsoft. New Microsoft is all about Azure, the walled gardens of windows is slowly being left behind. Take a look at .NET Core.

Oh please. Old Microsoft!? Sure, we all know there have been changes in management but you think that everything got changed just because they did OSS some technologies? Second, since when OSS is such a big deal? That's only a big deal to MS because world has changed a lot while MS hold still for a long time.

Take a look at DX12, WPF, etc. The walled garden is still there and getting worse, they're just sacrificing their other markets.

You are talking about destkop technologies that are necessarily tied with their desktop offering. When it comes to the backend/server side of things, Microsoft has making huge pushes to open source/extend their tools so that they can be used in other operating systems (mainly Linux.) My belief is they realize that the war for the server OS is kind of lost already, so they might as well offer tools that everyone can use on any of the many cloud platforms out there, while providing good tooling for their own PaaS solutions and make their money that way.

Old Microsoft wasn't that long ago.

Can't speak for what they intend to do, but current moves by Microsoft seem to be very much on the contrary direction of assisting migration or locking down existing citizens of their platform: Visual Studio Code, Roslyn (C# compiler), TypeScript, those are all cross-plaftorm. Not to mention the ones that are getting there, like ChakraCore (JS Engine).

Still having a hard time understanding the new Microsoft, but so far really seems like a 180" from the Microsoft of 10 years or so ago.

Since I first heard about CoreClr (or whatever they were calling it initially - .NET Core?), I've been thinking that they are gunning to displace Java, which is looking increasingly sad in comparison to C#.