Why do automotive sensors each need their own ground wire, if they go back to the same computer, which has . .?

the same chassis ground (0 V DC) to reference the sensor's return signal voltage to? A 3rd wire to / from every sensor is an additional expense thoughout the wiring harnesses.|||The circuits that read the sensors have what are sometimes called floating grounds.Although the circuit power is biased to chassis ground, the readings are not.Compare it to the radio amplifier and speakers.The speakers are running on a separate ground while the amp is at chassis ground.|||casey your losing it. remember you have to rely on resistance. its finicky.