Agreed.

I don't mean to sound pedantic. And you DO have a point about the operator bearing some sort of responsibility knowing there is a stoplight/stop sign whatever at the bottom. But, a few times when descending a hill we have locally, I grabbed the brakes and they scrubbed off about 30 mph, and then there was just nothing more to be had. As hard as I could squeeze, the bike just stayed annoyingly at 20 to 25 mph and wouldn't bleed off any more for a block or more. Eventually as a last ditch effort I reached my foot back and held it against the tire like we used to do as kids on Bmx bikes. I stopped IN the intersection, surrounded by cars. It was embaressing. Similar has happened just getting down to zero from 25mph when a car just decides to stop mid-block on some steep downtown streets here in Seattle.

You are right, it is a design limitation & that is why road brake rotors are the way they are as noted by OP, to mitigate or address the different duty cycle road brakes face.

Rim brakes work well. So does sitting up for aerodrag, both have other risk/benefits& is off topic as to the difference between traditional road/mountain rotors. Although both would make good for a new thread.