Wrong.
CASA does it that way because governments let CASA and want CASA to do it that way.
CASA has the culture that governments want CASA to have.
The distinctions between the origins and evolution of the FAA and CASA are merely a manifestation of the origins and evolution of the governments of the USA and Australia, of which those agencies are a part.
Australians beg for more government. Americans arm themselves to stop the government.