I see single storey houses in new suburbs around Rouse Hill selling for same/similar as double storeys which shows me times are changing..
It's not really that the times are changing it has been like that for a long time in new subdivisions because 3/4 of houses are double storey there ends up being more demand for good single stories as time goes on. Where I live a 25 square single storey home 5-10 years old will sell for the same as a 32 square double storey of the same age.