Excellent statement.
Today's cars do not use electrical paths as earlier models did. Thus there is less need for grounding.
The mechanical interfaces are run over the CAN system (controller area network). These include heat, A/C, instruments, lighting control, etc.
All other control signals run over the MOST digital optical interface. All radio, voice, CD, nav, phone, etc run over this system as digital bits through a digital optical cable similar to that used in your home audio system.
Almost negligible ground requirements.
Don't get duped.