You can make ABS systems without the pump. They take use the driver's input instead. That's how lots of early systems worked. You give up a little stopping distance in the case where one axle or one side of the car has a ton more traction than the other (think like driving in the gutter of a really strongly crowned road in a downpour) but they work pretty good and are CHEAP, like real cheap.
Throttle control is necessary because you need to lock the driver out of the throttle for ESC. Think of ESC as basically preventing soccer moms from mashing the pedal and getting sideways unnecessarily. Depending on how sideways they get initially the ESC programming is going to want to drag certain brakes to help get everything good again and that requires a pump since the driver's foot isn't there to give pressure (it might still be on the gas).
Throttle control is necessary because you need to lock the driver out of the throttle for ESC. Think of ESC as basically preventing soccer moms from mashing the pedal and getting sideways unnecessarily. Depending on how sideways they get initially the ESC programming is going to want to drag certain brakes to help get everything good again and that requires a pump since the driver's foot isn't there to give pressure (it might still be on the gas).