Despite best efforts .NET is still not an open platform
This sort of thing has been MS's playbook since I was a kid, or earlier.  It surprises me that people are still surprised when things like this happen.  I especially think someone with Miguel de Icaza's experience should know better[0].It's interesting to see the generational difference here. Many of my somewhat-younger (even only by 7-10 years) programmer/techie friends just don't remember the Microsoft of the 80s and 90s, and see all the "good" they've been doing with the open source community in more recent times, and think MS is a pretty good corporate citizen in the tech world.But in reality, MS has just done a great job whitewashing their image[1] in the past 15 years, especially in the past 8 years since Ballmer stepped down and Nadella took the reins. I do believe they're a better, less anti-competitive company than they used to be. But they're still the same company in many ways. I think a big part of their "play nice" strategy was born out of necessity, since they heavily dropped the ball in the late 90s/early 00s when the internet/WWW was really coming into its own, and then again in the early/mid 10s when Windows Phone failed miserably. They just lost the clout to do the anti-competitive bullshit they used to pull. But the desire to do all this stuff is still there.[0] It was clear to me that MS intended .NET to be a wholly-proprietary, Windows-only technology until de Icaza and co. built Mono, when MS grudgingly embraced it.  This proprietary extension feels like their standard follow-on of "extend and extinguish", though it's coming a bit later than we'd expect.[1] Bill Gates has also done an amazing job rehabilitating his image through philanthropy.  A lot of people forget how his actions at MS probably held back progress in the computing industry for at least a decade (or two?), through forced lock-in and anti-competitive behavior.