There is a lot of information about airflow around cylinders. Eg [1]. The top left diagram should be the one that applies with small diameters and the kind of airflow rates in a PC fan.
I would guess that all the other shapes have micro-scale sharp edges that leave vortexes which both slow the flow down and make noise.
That said, my current PC has plastic "angled slats" at the back (outlet) and a honeycomb and mesh (filter) at the front, so it could be quieter. I'll keep it in mind if I ever buy a new one. I believe the wire one was the most common on older PCs (90's / 2000's).
"They took a high-performance business jet, added extra drag, and ran the engines in reverse to simulate a flying manhole cover."
Like, even on cut or stamped grills, how much could performance be improved by e.g. sandblasting the finished piece from one or both sides and taking down the edges a bit?
That tells me if you were to get a 1000x really powerful fan, then the grille would start giving turbulent flow, and might no longer perform the best.
Page with lots of details: http://labman.phys.utk.edu/phys221core/modules/m8/turbulence....
I even remember, when in mac clones used ultra-high-speed coolers, which now used only in rack devices.
And yes, ultra-high-speed coolers, has much higher speed and make turbulence.
Wind tunnels use honeycomb flow straighteners to take care of this.
A full blown analysis might use computational aeroacoustics software that can calculate the noise generated from solid geometry in a given flow. This field has advanced considerably since when the article was published due to newer methods like LBM. It'd be beyond the scope of journalism like this, but it is no doubt done by companies with resources like Apple.