How long/how long ago did you live in Australia? A lot of that stuff isn't accurate, particularly the stuff about duopolies:
- Most urban areas have a choice of dozens of broadband providers, since there has been separation of ownership of infrastructure (physical lines) and services provided over that infrastructure (ISPs) for almost 15 years now. Some more remote areas may only have a couple of choices ... but the vast majority can purchase ADSL connections from 10+ national providers, and many also have access to cable, VDSL or fibre providers on top of that. On the contrary, it's the *US* that is characterized by broadband duopolies - in most places you have a choice of the local DSL monopoly and the local cable monopoly.
- Cars? Huh? Australia has a range of makes available as large as anywhere else in the world. Ford, GM, Honda, Toyota, Hyundai, Kia, Mercedes, BMW, Volkwagen, Nissan, Mitsubishi, many others ... and some that you'd be hard pressed to find in the US (Euro makes like Skoda etc.) Perhaps you meant the choice of Australian-made vehicles? (in which case until recently limited you to Ford, GM, and some Toyotas)
Where Australia DOES have a stifling duopoly is in groceries: the two big supermarkets, Coles and Woolworths, account for the vast majority of supermarkets in the country. Aldi is making some inroads and there are local grocers still holding in in some areas, but it's still a pretty sad state of affairs.
You're right about prices - the cost of living is quite high (though, with the AUD only at 74 US cents now, it's a good 30% cheaper than it was a few years ago, measured in US dollar terms). But median wage is significantly higher as well, which offsets that to an extent.