I think ABS function is more helpful in electric cars to give them a smooth run and its done with ESC and motor which is mostly electrical. For gas cars since usually the break pads and disc are already set to drag slowly when the servo pulls the linkage to create smooth breaking action without locking the wheels causing spinning. If ABS is used for gas cars, then the linkage will need to be set for stronger break, and the servo needs high reaction speeds to compensate with the loss of breaking power during the servo's backing period and smoother drag. In this case, not only the break pads will wear faster, it puts a lot more loads on the servos. However, due to the design of common 1/8 and 1/10 cars, the break and throttle are connected to the same servo, unlike 1/5 scale cars where seperate servos are used, this may cause unstable vibration to the throttle, and so much energy will be lost during the larger motion due to the relatively long breaking linkage. And todays servo and radio settings and function are still far away form creating a smooth (un-noticable) ABS action (Most radios ABS frequency settings can only go up to 20/sec *rough guess*, in geometry in order to make a smooth (breaking) curve you need far more dots than 20). So the traditional breaking system is more suitable to function a smooth break for the smaller scale gas cars.
This is just my little thought on the efficiency on using ABS on gas cars. And please excuse my poor writing.