Flogging a dead horse, but I'm game:-
1) "...why can’t their (US) airspace be used successfully and safely in Australia?"
Firstly, because our own (ICAO compliant) airspace was successful and safe, so why change? Secondly, because it is NOT successful and safe in the US. Read Voices Of Reasons first few posts (You claimed to be impressed by them, then COMPLETELY ignored the point they were making). Australia had a BETTER air safety record than the US pre NAS. They have Mid-Air collisions regularly. We don't (or didn't). TCAS was largely developed because of the proven limitations of US airspace shown by the Ceratous collision.
2) "I believe that Australia should have the same economic and efficiency advantages as the USA – especially in aviation. Don’t you?"
Firstly, no actually economic benefit has been identified anywhere but in your belief system and rhetoric. Ask Bernie Smith. Secondly, NO. Life is a balance between economic advantage and social responsibility. You want economic advantage? Scrap ATC altogether! Very cheap! Your ideologically driven insistence that all things American MUST be better simply doesn't wash. It is up to individual nations to decide where their priorities lie.
3) "Could it not be that the US airspace system could operate successfully here and substantial amounts of money could be saved ..... without unique Australian changes and costs?"
NO! The system was set up to take account of unique AMERICAN conditions. If it is the best model for ALL places, why is it not used universally?
4) "...why do many insist that we cannot have the freedom and efficiency advantages here in Australia?"
Because US freedoms come with terrible price tags. Look at their homeless. Look at their gun culture. Look at their corrupt political system. We are close ENOUGH to being the 51st state, but luckily have had the sense to avoid the worst excesses of Americanism. Their Airspace reflects their (and I suspect YOUR) ideology. The individual (in his Citation) is all, and the majority (in their "Cattle class" 737) can go to hell. After all, was not the "Basically Criminal" action of the controllers (and I DO hope a very full apology is forthcoming for THAT little gem) not getting the 60 tonne jet to avoid the VFR lighty, rather than the other way around?
5) US pilots can have the freedoms that additional amounts of Class E airspace gives, why can’t Australian pilots have those freedoms?"
Have a read of these forums Dick. Because the professional pilots who fly the VAST MAJORITY of people through Australian airspace DON"T WANT THEM!!!