I'm still convinced that in the world of frontend development, Ember is the only framework that hasn't screwed over its users.

My guess is that at Facebook there's too many smart people with differing opinions. Hence, we have to do an insane amount of research to construct the grab bag of pulling things together. And once that grab bag is complete, Facebook says "here's the new cool way to do it".

Ember on the other hand has happily given you the grab bag and has helped you support your production happens with the most professional, enterprise release structure.

Disclosure: Used to do only frontend development with Ember but switched jobs and now use React/Ember