With open source you can never write that a project is dead, but in this case it can't really get any closer to dead. Cyanogen was the only credible alternative to a Google and to be honest it was more a hope than a credible anything.
As a fraction of the total number of Android users the number that had even heard of Cyanogen or Cyanogen Mod, the open source Android ROM that could be installed on a wide range of devices, is tiny.
Android is mainly open source, but not all of it, and going from the open source code to a running implementation of Android on an actual device is a big step. Cyanogen Mod was an open source Android ROM which could be customized to run on any given hardware. If you were dissatisfied with the support your phone or tablet was getting from the manufacturer then you could DIY with Cyanogen Mod - but only if your device was listed as one of the available downloads.
Your opinion of Cyanogen Mod depends on this availability problem. In all the years I attempted to upgrade a device I can honestly say I never manged to find a compatible image - the closest I got had health warnings all over it as an early experimental image with no support. Perhaps it's the type of device I tend to use, but it still made Cyanogen Mod irrelevant as far as I was concerned.
As an open source project Cyanogen Mod was always a fun proposition. Then in 2015 something strange happened. Kirt McMaster CEO of Cyanogen, a spin-off company designed to make Cyanogen Mod a commercial success, decided to announce that it was going to destroy Android (Google's Android that is). The most famous quote was that he was going to put a "a bullet through Google's head". This was just silly and at best over-aggressive nonsense. There was a chance that Cyanogen might snag a few manufacturers eager to get away from the ever stricter control of Google, but there was zero chance that it would take over, or even make a serious dent, in Google's control of Android. To do that Cyanogen would have had to provide a range of services that go well beyond simple Android - Google Maps, Play, Google+, Drive, Ads and so on. In many cases it would also need to add apps that provided access to Google services such as Gmail and Drive, and Google might not be so helpful in this area. Add to this the fact that any company using a non-Google Android has to stop using Play on all of its devices and you can see that the chances of anyone opting to try out Cyanogen Mod commercially are very slim. Even so, Google did make an offer to buy the company, but this was turned down.
Of course this is all with the benefit of hindsight. At the time Cyanogen had partnered with a small company OnePlus to make low cost phones and with Microsoft. Even though it seemed unlikely, one possibility was that Microsoft might use Cyanogen as its secret weapon against Android proper. As things turned out Microsoft had a different strategy and one day we might even find out what it is. ,
Things have been quiet until the Friday before the Xmas break when Cyanogen announced that
“all services and Cyanogen-supported nightly builds ... no later than 12/31/16.”
adding that the source code
“will remain available for anyone who wants to build CyanogenMod personally.”
This follows workforce reductions and a suggestion that apps rather than the OS would be the focus for the future. Cyanogen may be dead, but the future for Cyanogen Mod isn't quite as clear cut. The open source programmers have announced that they will press on with the project with a new fork called Lineage OS - which is arguably a more saleable name than the weird-sounding Cyanogen.
"Embracing that spirit, we the community of developers, designers, device maintainers and translators have taken the steps necessary to produce a fork of the CM source code and pending patches. This is more than just a ‘rebrand’. This fork will return to the grassroots community effort that used to define CM while maintaining the professional quality and reliability you have come to expect more recently."
If you have a Cyanogen Mod ROM installed there is no reason to change it, but don't expect any more updates. As to Lineage OS, well in theory it should be just Cyanogen Mod under a different name, but waiting to see what happens would be a good plan.
So is this just a story of everyday open source folk being overtaken by megalomaniac management types out to dominate the world and make a quick buck along the way?
It all goes to show that open source isn't as simple as free software or free beer.