Now it's official, Firefox OS moves into the „Tier 3“ support category.
Tier-3 platforms have a maintainer or community which attempt to keep the platform working. These platforms may or may not work at any time, and often have little test coverage.
Quote from MDN — Supported build targets
… So this basically means there won't be any extended effort to make Firefox OS more stable, or to make it even more user friendly. Also, there won't be any new advertisements to get a wider user base.
Don't understand me wrong, this should not be a post of any upset Firefox OS addicted. Even if I'm one, I will try to be objective.
The lost of Firefox OS as phone operating system means to loose some diversity. So why should I care about diversity? If everyone just uses Android, doesn't that mean more development work is moving into Android and at the end, every user will benefit from that? Short answer: no.
So why ist the lost of diversity so important to me? Less diversity means less competition. And competition keeps companies to focus on features that are important to users. Let's say Android does not implement the new cool feature, that iOS has. So users will shift to iOS. Let's say this feature has to do something with your car. So if Android implements this feature in their own style, car manufacturers now have to implement two proprietary technologies: Android Auto and Apple CarPlay.
If there is more diversity, like with Windows Mobile, Firefox OS and so on, these companies have to talk to each other and try to find a general standard. Because car manufacturers won't implement four+ technologies that basically do the same thing.
So the lost of diversity, at the end, means the lost of improvement / development of standards. And there's no way for „newcomers“ to get into the market (without paying a lot fees to use those proprietary technologies).
One small example, I've a new car with some fancy radio. This radio has a hands-free phone system based on Bluetooth. This was standardized some time ago, so now I can connect my Windows Mobile and my Firefox OS without any problem. This radio also has Android Auto and Apple CarPlay support. I simply can't use it, because it's proprietary technology. Android and iOS together have so much market share, that it's not necessary to develop and implement a better standard.
With no competition, companies can basically „do what they want“, because there are no alternatives for users.
Firefox OS was never seriously competing against Android/iOS, because it arrived too late for that, and Mozilla doesn't have the same business impetus and formidable resources that Google/Apple wield.
However, it is a clever piece of technology with some very nice and unique properties, e.g. a very light software base with better performance potential, and the proven privacy and security models of the web. I also like to believe that the project helped with and pushed others to standardize many mobile-related features.
Note: I've been using Firefox OS as my only phone for more than 2 years, and I intend to continue using it as long as it's not broken (although as a developer and Mozillian, I'm arguably more receptive to its ideology and technology rather than human-centered aspects).
One example: Bringing the web's fantastic permission model to mobile apps. On Android/iOS, you need to grant every permission an app might ever need at install time, forever, without any granularity. Instead, a web app (even installed apps in Firefox OS) will ask you for a specific permission when it actually needs it (e.g. "can I geolocate you?", "can I read your contacts?"...) and you can say "no" whenever you want (I'm looking at you, Twitter).
These issues were going away. I think Mozilla recently gained official support for Firefox OS on Nexus devices, and there is a CyanogenMod-based porting solution somewhere in the pipes to support many more devices (only rumors here though, don't take my word for it).