did you know that AsA was awarded a contract by the FAA to run several class D towers in the USA? Utilising the same airspace model they claimed was unsafe in Australia? And no, class D towers in the US don’t have radar, their tower controllers aren’t required to be radar rated, they administer the airspace within about 5NM of the aerodrome. And yes, they are a damn sight busier than Australian Class D, with 121/135 and 91 operations.
And we all know how well that all turned out, don't we?