They are very open that this is not their plan here. They are _temporarily_ forking Node.js to add support for their JS engine. They want to extend Node to abstract away the JS engine so that it doesn't rely on V8 or Chakra or SpiderMonkey but can sit on any one of them.

It's actually exactly the opposite. Their API abstraction work will only increase competition, especially since they aren't trying to run a competing fork. Despite their history, those in favor of a more open Node.js platform should commend this.

To play the devil's advocate of the devil's advocate, how exactly would an [x]extinguish work in an open source world especially for something that is under a liberal licence (MIT vs GPL)? Isn't that the whole point of open source? That if even something gets abandoned or ignored, as long as there is still an active interest in it, it can still be used or improved upon?

You're probably aware I'm not considering it to be likely that this is Old Microsoft in action but to humour the thought experiment: I don't think they could succeed either. IE is still only barely recovering from Microsoft's history and Windows has largely been defeated by OSX both in the consumer and developer space. We're unlikely to see Microsoft Space Nazis descend upon us from a hidden moon base any time soon.

That said, there are plenty of examples of the extinguish phase not working out or resulting in less of a bang and more of a whimper. It's always been more of an infected blanket than nuclear warheads.

Extinguish Javascript? Good luck with that.