That's mostly true but perhaps a bit simplistic.
The demographic pie can be sliced in several different ways, and some ways split Labor down the middle, which is a serious problem for the party. Slicing it into rural-and-regional vs major cities: rural and regional people are mostly more conservative socially than urban people, so Labor's rural/regional base is more conservative than it's urban majority. The National Party doesn't have that problem (it has no real urban membership, so it isn't split) and neither do the Greens or the Libs (for the converse reason - no rural membership to speak of).
An increasing number of rural people are concerned about the environment (climate change, species loss, erosion, land ruined by coal mines and fracking, etc) but feel that the Greens don't understand those issues in the same way that they do, and they are not really wrong. Add that to the country's suspicion of the city, and the difference in social views, and the Greens seem doomed to remain an urban party.
But what I've just said applies also to the left of the Labor Party.
One thing that happened to Labor this time was that they sat on the fence on Adani's Galilee Basin coal project and lost votes to both the rural/regional and urban Right (for not approving the project) and to the mostly-urban Left (for not definitively stopping it).