So, it's nice to hear that he's making concrete steps forward, but the bottom line is that he's still not open-sourcing it, just continuing to promise to open-source it, as he has been doing for many years.
With that in mind, I think the title of the HN post is misleading; it would be more accurate to entitle it "Not Open-Sourcing Inform 7", and still better to entitle it "Not Yet Open-Sourcing Inform 7."
And that's a shame, because Inform 7 looks like one of the most interesting experiments in programming-language design today, and has been for years. Years that I haven't tried it, because downloading and installing proprietary software is not my idea of a fun pastime.