Racing cars brake later rather than harder
What limits deceleration, and why the limit is not the brakes.
Racing cars brake later rather than harder because the brakes themselves stopped being the limiting factor a long time ago, and how hard a car can actually slow down is set almost entirely by how much grip its tyres have, a limit that pressing the pedal harder cannot push past.
The tyres run out before the brakes do
A modern racing brake system can lock a wheel solid with only a fraction of the pedal pressure available to the driver, so the brakes have more clamping force on tap than the tyres can ever use. Once a wheel locks, it stops rolling and slides, and a sliding tyre generates less deceleration than one still rolling at the edge of its grip. Pressing harder past that point slows the car more slowly, flat-spots the tyre, and takes away steering at that wheel entirely.
The real ceiling on braking is the grip the tyres have available at that moment, set by the same tyre and weight-transfer factors that govern cornering. Brakes far larger than a car strictly needs therefore do little for a single stop once locking is avoided. Their benefit shows up over a long run, where they resist fade.
Digging in the heels on wet grass
Trying to stop while running by digging the heels in harder on wet grass makes the same limit obvious. Past a certain point, pushing the legs down harder only overwhelms the grip between shoe and grass, the feet start to slide, and the stop gets longer and less controlled than it would have been with a slightly gentler push. The muscles, like the brake pedal, can apply more force than the ground underneath will accept. Easing off a little the instant the feet slip restores grip almost immediately, the same recovery a driver makes by releasing a fraction of brake pressure the moment a wheel locks.
Half the grip, twice the distance
The distance a car needs to stop from a given speed is inversely proportional to how hard it decelerates. A driver who brakes at only half the deceleration the tyres could support needs twice the distance to shed the same speed, so the one who uses the full grip from the first instant can wait until much later to start braking and still make the corner. A road car on ordinary tyres can slow at about one g, the same rate at which a dropped object gains speed, and at that rate it stops from 60 miles an hour in roughly 37 metres, ignoring the driver's reaction time. Braking at half that rate from the same speed takes about 73 metres, and the difference between the two is around eight car lengths of road on which the later braker was still travelling at full speed.
The skill in braking late is reaching the tyre's maximum grip the moment the pedal goes down and holding the car at that edge for as long as possible before easing off into the turn. That is hard to do well, because the driver works at the edge of grip for the whole stop with no comfortable margin, and a small misjudgement costs either a locked wheel or a pedal released too early. Drivers stepping from road cars into racing cars for the first time often lock wheels early in a session, pressing far harder than any road car ever needed.
Anti-lock systems and brake balance
Anti-lock systems on road cars work by preventing exactly this wheel lock, releasing pressure automatically the instant a wheel starts to slide instead of letting a driver's instinct to push harder cause it. Brake balance matters for the same reason. When neither the front nor the rear tyres lock before the other, both ends contribute their full grip to the stop, and a car that locks one end early is wasting grip at the other end that could have been slowing it the whole time. Getting that balance right does more for stopping distance than almost any change to the brakes themselves, because on every braking zone of a lap the job is managing tyre grip precisely, and extra force beyond what the tyres can take is wasted.