Dick, And this assessment is based on what? May I suggest you spend a few hours on a few different days over a few weeks in both Melbourne and Brisbane Centre, this may validate your claim.

My question was not one based on a workload comparison between USA and Aus but specifically on sector sizes, given that my sectors are larger than most FIRs.

Further, my question was one for USA ATCOs.

And golly gosh, it's 10pm in the Australian Eastern states and there are still 150+. Roll on to 2am and even then there were 90+.

Wrong!

Not one designated Terminal in Canada is Class E airspace.......

Low level Enroute sectors have absorbed airspace such as Saskatoon, Regina and Thunder Bay. They are controlled by Enroute controllers, using radar, not Terminal controllers.

One more thing that we do (or did) in the US was take over terminal airspace that is not open 24 hours. We provided approach control services there in addition to our own terminal areas within our en route (area) sectors. And these sectors are combined and huge for US area sectors. (And still no approach rating.) I've been retired US ATC 8 years but I would bet they still do that.

I never minded, but others refused to ever vector for approach and would require the pilots to fly airways and transitions and entire approach procedures.

Yes, still very common for centers to take over approach control responsibility, generally after 2100-2200local when the approach control closes. Off-hand, it happens in parts of Oregon, Washington, central CA. That's in addition to the may more uncontrolled airports (or Class D with no associated approach control) for which the center always handles those duties.

Don't forget the center controllers who provide clearance delivery on the ground for aircraft awaiting to depart, too (obviously only works if there is an RCO nearby).