NOt denying its a great place...but when it comes to population, density and infrastructure Sydney has nothing compared to the other major cities mentioned and also nowhere near as accessible globally....not really comparable.
Any non-local driving through some of the places you can buy in Sydney for $900k will immediately think "overpriced back alley hick town"
I agree Sydney is one of the most beautiful places in the world....lets think where though? Inner Sydney, Beaches, National Parks and Blue Mountains. Everything in between is just a sprawling suburban mess with terrible roads, terrible public transport, old fibro houses and the commute alone to any of these "beautiful places" will take up most of your weekend.
Maybe I'm being pessimistic. Who has a million to spend on an "average" property nowadays?