I don't think the word "Bluey" is dying out - my youngest children, aged 3 and 4, recently were given a ginger kitten, and were allowed to choose his name themselves. Yup you guessed it: "Blue". Maybe it is intrinsic to human nature to choose opposites as names - when asked by Dutch friends to explain why the cat is called Blue, they shrug and say "He's red, so he's 'Blue' "