No it’s not losing it’s “gold standard”. Their customers want it and CAAC has been working with the FAA for many years on building it’s expertise as a civil aviation authority. The FAA was working with them on the ARJ21 but had some issues with their process. If you knew anything about type certifications you would know that both Boeing and airbus receive their type certificates from their respective civil aviation authority(FAA for Boeing and EASA for Airbus) once they get a certificate from their home regulator they very easily earn certification from the remaining CAA (either the FAA or EASA). In fact many times the type certificate testing is done jointly with EASA and the FAA issuing at the same time as there are bilateral agreements in place.
No airliner can fly in the US without a type certificate from the FAA. I can’t think of any Boeing or Airbus that doesn’t have type certificates from both agencies. Just because the EASA has agreed to take a look at the plane does not mean it’s going to get a TC and the FAA will suddenly become irrelevant LOL. Truth be told the 919 is years behind the 737MAX and the NEO and cannot compete with them and they don’t have to because their own domestic market is demanding a cheap plane and it fits the bill. Unlike China, Norway has very high standards for it’s equipment so naturally they operate an all Boeing fleet.