obviously wheel aerodynamics are much more complicated than frontal area. obviously nobody runs 20mm tires anymore...
Yes it is, but generally if you have the same shaped object but that object's frontal area increases then so does its drag. Track bikes use 20mm tyres. Another example of where aerodynamics and rolling resistance are very important but since they're not worried about pinch flats, they don't need to widen tyres. Do you see any track teams running 30mm tyres? No, of course not, because they'd be slower. Wider tyres are used to deal with 'terrain' and wider wheels are more aero than skinny wheels with wider tyres, not simply because wider is more aero.
What isn't right about Crr? "Even if you did run them at the adjusted-for-comfort pressure, as you say, the Crr is basically the same, so no advantage in going wider" is literally what you said and everything else I wrote is lifted from the article you linked to.
Maybe. Or maybe he wouldn't have even made it to that point in the race on tubeless.
Slowing down one-handed with a flat front tyre is not the best way to remain upright no matter what your choice of tyre is. When the peloton is racing on tubeless tyres, maybe then I'll believe the hype.