No, they have a full hallway of people working on it and job openings on the careers site, and a good chunk of Azure core services use it with new services still being built on it.
Supposedly it's pretty nice, since if you make sure to deploy your instances to different AZs, it takes care of synching all your in-memory data between instances and you can treat all of your data as in-memory data. You don't need a separate data layer, and supposedly everything is robust because you've got resiliency across AZs. At least that's what I've heard, though I've never used it and am curious about the actual resiliency and race handling.
Do you know why the oss project is stagnant? It would seem if they wanted it to gain traction they would use that repo as the main one. Someone else mentioned service fabric was for stateful services, but at this point stateful services in kubernetes are mature.
