Maybe, but the question remains, is it viable now? Is Firefox OS viable now? The answer to both is an emphatic no. However it's felt more in regards to Mozilla

Maybe, but the question remains, is it viable now? Is Firefox OS viable now? The answer to both is an emphatic no. However it's felt more in regards to Mozilla as they don't have the resources to build Firefox OS and maintain Firefox along with other projects like Thunderbird. Android still doesn't have a good open source mail program and the port of Thunderbird was a hope.