Melbourne's transport system is indeed largely built around getting everyone along spokes into the CBD.
Sydney is a slightly different beast though. Its transport problems stem from a mixture of geography, history and lack of/inept planning.
Its roads are generally thinner and crazier due to being a more "organic" in its early planning compared to melbourne (which is built in a planned grid). Sydney literally tore up and destroyed one of the biggest tram networks in the world and converted the roads to automobile.
Meanwhile the combination of the harbour, sea to the east, blue mountains to the west create an increasingly geographically constrained city. Transport options are severely limited out to the eastern suburbs (cynically, partly by desire, they are also the wealthiest suburbs in general). Contrasted with melbourne, which is built on a massive flat plain around a bay, Sydney terrain encompasses hills and valleys to a far greater extent further limiting the engineering options.
Finally, sydney's main airport is comparatively close to the main CBD (almost half as close as melbourne's) which is further limiting the available land within the central area, and resulting in requirements to build a second airport out west to try to increase air capacity to the city.
The result, along with australia's cultural and historical proclivities is a city almost in constant congestion, highest house prices, and with easily the longest commutes in the country. (keeping in mind when viewing comparable stats, that although sydney is out in front, I felt many sydney-siders will rationally try to compensate/substitute their travel times to avoid the congestion).
Lived in both myself. All major cities have congestion, but its at another level in Sydney compared to the other Australian cities. The culture in the office of "accepting crazy travel times to get into work" was insane.