There is just over 200 CX pilots based in the USA. 17 leaving seems to be a significant number. A lot of the USAB FO have applied elsewhere. However, it takes time to get an interview and course.
The onshoring will be very interesting as some USAB FO are preparing an age discrimination grievance and I am sure if it is not resolved by the time of onshoring that this issue will go to court. Not to mention the paycut related to this and the lower then HKG pay rise offer for USAB officers.