Hong Kong exists in spite of China - not because of it - do you not realise that the communists hated the very notion of Hong Kong?? HK is capitalist and was basically always a Western outpost. Even the Central Government today is ardently trying to divert investment and growth away from HK to the 'new' financial capital of the East, Shanghai. HK existed only as an entrepot between the developed East (Japan, Korea, Taiwan) and the West. Its economy today is suffering as a result of China's neglect towards it - just ask any banker who has worked there since before the handover.
A new city in Australia would be entirely different from HK, so you seem to have missed the point there too. Australia should not try to build a trading port because all of Australia's trade goes out of other ports already. As Bernard Salt said, Australia needs a new northern city simply to cope with population growth - it starts and ends there. Melbourne and Sydney for all intents and purposes are already full, and cannot grow much more without diminishing existing living standards. And Australia's south is getting drier, while the far north has much more rainfall. After an initial government investment, natural, sustained organic growth would ensure that private industries grew and gradually replaced government institutions as the key source of employment. Just look how government expenditure as a result of ACT's GSP has decreased from virtually 100% in 1930 to only about 60% now - and that city's growth has been severely retarded by nimbyist politics and extremely poor urban planning.
Any new city built in Australia no matter where it was could only come about as a result of huge government investment. But the benefits of diversifying Australia's population could be equally huge over the coming decades as it allows more 'breathing space' and less cramming of existing cities IMHO, enabling the country to continue along a strong population growth trajectory without seriously impacting living standards.
And over the long term, there is absolutely no doubt that continued population growth would make Australia's defence force stronger too. Population * incomes = economic power = military power, in blunt terms.
Your knowledge of history is as poor as your knowledge of economics. Hong Kong flourished for 100 years before the communists ruled China, & flourished even more after they took over the country. With the demise of Shanghai as a financial & trading centre, Hong Kong became China's window on the world. Far from it existing in spite of China, the communist party has, apart from brief spells, protected it. Communist China provided Hong Kong with water & electricity for many years, & directed a large part of its foreign trade through it. Its economy is doing just fine at the moment, growing fast - but expats are no longer paid grossly inflated salaries, so their personal economies are not doing well. I thought everyone knew by now that the incomes of bankers are not a good reflection of the health of an economy.
HK was founded as an entrepot between China & the West, when there was no "developed East", & has always filled that role. It has never had a significant role as an entrepot between S. Korea, Taiwan & Japan & the west, but has been an important entrepot between Taiwan & China. Shanghai is not the new financial centre but the revived one: until WW2 it was a greater entrepot & financial centre than Hong Kong, centred on the International Settlement, where Chinese writ did not run.
You say that a new city could only come about as a result of huge government investment. By saying this, you are admitting that you are wrong. How can you not see that? If there was a sound economic basis for it, government investment (in infrastructure, etc) would follow organic growth, & be largely financed by it, as elsewhere.
Rainfall is not a reason to build a city. The west coast of Chiloe has very high rainfall - but it's a lousy place for a city, & only has one village. The towns are all on the drier east coast.
Australia is not exactly crowded, & there's no shortage of water for drinking & washing. Is Newcastle full? And what about existing northern towns & cities? Townsville? Cairns? Darwin? Katherine? Why are these places not growing at spectacular rates, if the north is the place to be? Katherine has an airport, a good railway, roads. Its produce can get out & imports can get in easily. Surely, if it's such a good region for growth, it should have tens or even hundreds of thousands of people.
If this hypothetical city isn't going to trade, how will it live? It can't be a dormitory town for other cities, because it will be remote from them. What will its people produce? Where will they get what they consume, without trade? You've not thought this through at all, have you?
I don't give a wet fart what is said by a self-publicist generating sound bites to sell his books, & I mistrust anyone who quotes such people.