A bit like extralite, I love PPrune because I learn what others are thinking, I can do without the personal abuse...but to turn to the subject.
Before Dick came along we had a Flight Service profession that had inherited legislation from the days when Australia was described by Flight International as the Police State of Aviation. Almost mandatory flight planning and traffic information everywhere. Dick brought a fresh pair of eyes and tried to turn Australia into a place where you could fly a plane just like you could drive a car or sail a boat. Just the regulation that was required to keep a reasonable standard of safety. Unfortunately he called it Affordable Safety because that is what it was, and has been caned for it ever since.
Dick brought MULTICOM and UNICOMS to Australia which is why we call them by their US names however there is no equivalent regulation to the FCC stuff quoted on this thread. CASA does regulate UNICOMS in a light way but as far as I am aware anyone can pop-up on the CTAF and offer a service. All they need (and this is the light regulation) is an Aviation Radio Operators Certificate (AROC) unless they are a pilot when the AROC privileges are included with the pilot licence. If you want to be a weather observer the BoM will train you and CASA will then approve you to pass the observation to pilots; this is the CAR120 approval. There are at the last count 22 UNICOMS advertised in ERSA, and AIP has some advice about what they can pass to pilots in the way of information. It is fine to say that anyone should be able to pass weather and traffic information but I suggest that people are thinking about a nice sunny sky and a couple of aircraft. Try thinking about a dirty rainy day, marginal VMC with scud-runners galore and a couple of pilots trying to make an instrument approach. Should someone at a UNICOM who is untrained take it upon themselves to give a weather observation or traffic information to a pilot who then got into some sort of dangerous situation, can you imagine the furore and where the buck would stop? At CASA, that's where, and quite rightly so because CASA is charged with oversight of our aviation system.
So due to political pressure (that's another word for you, Dick) CASA came up with the CA/GRS and some UNICOM trials to see how this level of service might work. I understand that there was universal condemnation of the UNICOM trials run by Airservices so CASA rejected the concept of regulated UNICOM but stuck with the CA/GRS. This is after all only a souped-up UNICOM where already trained radio operators are provided with a regulated minimum suite of equipment and certified to be able to provide weather and directed traffic information. In both the CA/GRS that currently exist they are ex FSOs or ex-ATCs because they are the only source we have of trained operators. (No - pilots are not similarly trained) I can only guess at what the cost of replicating ATC/FSO basic training would cost but I doubt that an off-the-street, which includes firemen and baggage handlers, CA/GRO could be trained for less that $30,000. Airport safety officers are in a slightly different category because many of them have BoM qualifications and could be CAR120 approved to pass weather, as by the way can any UNICOM operator - but not traffic. So it is possible to have this so-called no-cost service called a UNICOM but no-one seems to want to do it. On the other hand if you want to improve safety at an airport why not employ some retired ATCs or FSOs to provide traffic information?
It seems to me that we have is a good old-fashioned compromise that accepts that our system is different while trying to capture a good feature of a different system.