I think that it's important to get people to start off slowly and not just dive into every operator and being "fully reactive". I recommend people start small and just learn how to subscribe to observables, maybe try filter and map... then work their way up to merging, error handling, etc.
No. I don't think Ember and Angular will be merged. I think they share a lot of ideas, and despite a perhaps thorny past, the two teams seem to get along pretty well, and there's been some collaboration between the two in recent years. In particular the initial AngularCLI was based directly off of EmberCLI. But I don't think they'll merge, they are two different organizations run by two different types of entities.
Some of it is echo chambers. If you're in the React community, that's all you'll hear about, same for Angular. The Angular conferences I've been to are MASSIVE. Easily some of the biggest conferences I go to. I don't think it's going bad for Angular at all, and I've seen a lot of growth.
Now that said, I do think there things Angular can do to improve, and I know they're doing those things. Making Angular simpler and faster being the primary thing there.
Well, in my day job I work directly with other developers, who are all brilliant folks, in-person. I eat lunch with them. I have a lot of design reviews and meetings and such. In RxJS I'm working with brilliant devs as well, but it's a little more asynchronous, meaning that I don't get a lot of face-time, and a lot of the work is done in my off-hours and spare time, then communicated to someone like OJ Kwon for review.
So overall the feel is just different. Not better or worse. I do wish I could work in-person with other RxJS contributors, but that's just not how OSS works usually.