Surely how the driver applies the brakes matters. Perhaps 72bluNblu is arguing that one can apply more finesse with disk brakes than with drums to come closer to that "just before skid" point. Not sure what his "stab" refers to and sounds like a jiggy driver. I doubt a competent factory design would show fade (friction material melts) in drums when braking from 60 mph. The other issue is having all 4 brakes perfectly matched. Drums are touchier to slight friction changes, due to their self-amplifying effect (has to do with where the pivot point is and if fwd and rear shoes interact - "floating design"). In worst-case, gummy junk on drum shoes can make them self-lock. Perhaps trickier to insure L & R front drums are matched, but if all parts are clean and new they should. Caliper pistons can get sticky to vary L & R. Front to rear proportioning is also important, and varies when you mod the car's weight distribution. I wonder how close the factory gets it, and they likely err on the side of rears skidding quite a bit later than fronts, for safety.
Most newish cars have ABS. My 1996 Plymouth does and it was the absolute base model (4 cyl minivan, newspaper ad), though rock lists non-ABS driveshafts so maybe even cheaper ones. My guess is that in braking tests, they just jam the brake pedal and let ABS take over. That should give the very consistent data. Theoretically, a very competent driver might brake faster than ABS, but hard to know where that skid point is. How ABS "chatters" probably has a big effect. I suspect that because early Tesla Model 3 showed poor ~150 ft stopping in Consumer Reports test, akin to a pickup. They did an over-air software update and it dropped to a normal sedan ~125 ft. My guess is they boogered with ABS settings, since they had softened the suspension design a few months prior so perhaps hadn't re-optimized ABS settings. But, also might have had to do how regenerative braking is set. BTW, tests have shown minimal benefit from ABS as many drivers are scared by the chattering pedal, thinking something broke so let up on the brakes. Need to practice it in a snowy or wet parking lot so you aren't surprised in the real world. Just keep the brake pedal jammed down.