Yeah, this has been a big disappointment to us too. When we talked to Dish about moving back to Dish from Directv this year (which we've done) the person I talked to assured me that Netflix would be on the 4K Joey's "within a month or so" - this was in August - and so we went with the 4K Joeys instead of the regular or wireless Joey. Made sense - it's working on the OTHER Joeys, Working on the Hopper 3, of course it is going to be on the top of the line Joey.
I know, never believe the customer service people (I've had satellite since 1995.) I will be fascinated to find out why the 4K Joey is so different from the Hopper 3 and the other Joey's that it has taken so long to get Netfix on it.