It's funny how open the market for browser automation is. Everyone needs to switch off phantomJS in the next few years and is looking for the easiest option.
Sadly, there's probably no money on the line. But you will get your buggy software used by huge corporations for years to come!
There was still some commits in early July but haven't seen new updates till date. Maintaining a browser project is mammoth task. Even for an established startup such as Segment you see that NightmareJS has lots of issues unreplied for months. I guess it's primarily because of a potentially large user base and all kinds of edge cases requirements from different users. And add on to that, suppose to work on all OSes. Nightmare.
Sadly, there's probably no money on the line. But you will get your buggy software used by huge corporations for years to come!