The first class of airspace that meets the design separation assurance standards, and which, by definition, proceeding beyond (ie C instead of E) provides no additional benefit for the additional CNS/ATM resources and other associated costs expended ---- in other words, "economic waste".
Correct!
That is the fundamental issue you and Mr Smith refuse to acknoledge, that is:-
Australian Class C, and 'full' ICAO Class D and D/C [by a tower/approach combined controller] are operated 'efficiently', when compared to US practice [where similar levels of RPT traffic with a pax seat capacity >30] at airports with similar numbers that are class C
WHY?
Lets spell it out so there are NO misunderstandings:-
1. Australian Class D and D/C towers service similar numbers of 'large RPT' aircraft as many of the US class C TMA serviced airports
2. Australian Class D and D/C towers on average service less numbers of VFR than US class C services
3. All class C terminal areas in the US are radar covered
4. Australia has no such radar saturation [except at the primaries]
5. Because of the comparatively less VFR activity at Class D and D/C locations in Australia, ATC can provide non-radar ICAO D and C services without saturation
The bottom line:-
A. Australia does not need US Class C, radar equipped, Tower and separate Approach and Departures staffing [average 30+ per terminal in the US] at regional [non-primary] ports
B. Australia does not need to force pilots [both IFR and VFR] in VMC to be 'primarily' responsible for 'see and avoid' as is the case in the US
C. Australia does not have the traffic/frequency saturation to necessitate the use of Class E [surveillance based or otherwise]
D. Australian industry cannot afford to use US Class D and C terminal area rules [due the associated ATM infrastructure required]
E. Without a similar investment in terminal area ATM infrastructure, the same radar based safety net [which Australia offsets by utilising third party active collision mitigation through
ICAO D rules] used in the US would be absent in Australia, where [as already pointed out] large numbers of large RPT's operate
F. Australian industry can afford [for no extra cost above class E] to run regional tower based non-radar ICAO D and D/C instead
Both countries may claim ICAO compliance, the difference is the level and type of CTA/R service assets needed to achieve the desired sovereign legislated safety outcomes.
With those realities in mind, which of the two countries 'system safety' outcomes would you consider superior? and why?