Dick the situation you describe in your first post was many years in the making and probably stemmed from the same malaise that we suffer from now - lack of long term planning. Civil Air and PREI have nothing to do with it, they are simply representatives of their members. Ex-FSO Griffith adequately describes the relations between FS and ATC throughout the 70's and 80's egged on by the various supervisors who did not know any better and radar was never going to be cost-effective in the hands of FSOs due to the capital cost and the training. If the traffic was dense then enough introduce ATC as per Bankstown and the other GA metro airports. The traffic information given OCTA was always a luxury which no-one could afford.
The history is another thing and I like to think that ATC grew out of Flight Service and I am glad that so many of our FSOs were able to cross train when the opportunity presented.
I know more about the US than Australia but the history there is that the airlines got together long before the Grand Canyon and established Federal Airways, this was 1927. When radio became available around 1930 airport control towers were introduced (Cleveland Municipal had the honour) and the airlines initiated flight following in the federal airways for their own aircraft. They then got together and coordinated between airlines by phone before opening the first Airway Traffic Control Center in Newark on December 1st, 1935. Others were also opened coordinating movements between airlines and the airport towers. On July 6th 1936 the US Government took over the operations of the Centers but not the Towers as they had become the property of the airports. Flight Service Stations grew up at the sites of the four-course radio ranges and began to do remote radio for the ATC centers. They gradually took on more functions including passing known traffic information, but I don't think it was as heavily regulated as it was/is in Australia. They were also heavily oriented towards the GA community, something I think they had in common with Australian FSUs.
Flight Service in the US has gone the same way as in Australia, radio relay was no longer needed (except for HF which continues to this day), flight information could be distributed by computer making it possible for the FSUs to be withdrawn into large scale FSS. With that withdrawal the traffic information service also disappeared however the US seems to have lots of keen people willing to run UNICOMs whereas we have only 22 (I think) who we forbid to provide traffic information. Similarly in the US FS never had access to radar it was simply not their job. The US (VFR exempt) federal airways developed into Class E airspace and surveillance has enabled the US controller to provide a great service to IFR and VFR who ask for it.