The original ABS systems only modulated pedal pressure. Some systems only worked on two of four wheels.
"Better" or later systems could modulate all four wheels. Even more developed was the ability to modulate each wheel independently.
Modern systems have an electric pump, which pressurizes a reservoir. Sometimes you can hear them whine for a few seconds on startup (modern Honda Civic comes to mind).
These systems can compensate for "too much" as well as "not enough" pedal pressure. Through sophisticated electronics, they can possibly even do a variety of other tasks:
- Retard cruise control or steep slope descents
- Emergency braking triggered by proximity radar
- Traction control to redirect torque across a differential away from the slipping wheel
- Dynamic handling assist that can figure out
which wheel to drag in a corner and help steer/pivot or prevent spinout.
- Automated parallel parking assist
- Launch control
These are just a few off the top of my head. I'm certain there are several more, and more to come.
While you won't find Lauch Control in all but hyper sports cars, some Volvos have Dynamic Stability Control (they may call it something slightly different).
I'm not current with BMW and Mercedes offerings, but I do know that they offer a menu of features beyond "anti-lock braking" on the higher-end [more expensive] vehicles.
Even my lowly 2018 Toyota Sienna van (don't get me wrong; I love it) has emergency braking, traction control, and some other high end features which are effected with the ABS "pump".