The pax figures for Syd-Meb are extremely low. 280 compared to Syd-Bne 1400 or SYD-Gold Coast 650.
Sydney and Melbourne are Australias largest cities and even in the 1950s, this was one of the worlds busiest air routes. (4th busiest today)
Brisbane on the other hand was a bit of a back water and the Gold Coast was a small holiday resort right up till the late 70s.
Syd to Meb pax figures need to be increased by at least another 1000.