[Just for the sake of anyone else reading this discussion, who may be in danger of being confused or misled]:
Current flows in loops, from the battery, through a conductor, then through the load, then back to the battery via another conductor.
Each conductor has resistance, and the resistance of a car body is indeed likely to be less than that of a length of wire, but the choice to connect it to the terminal marked '-' rather than the terminal marked '+' doesn't make
any difference whatsoever to the voltage across the load.
Why? Because the load, the wire and the car body are all electrically in series. The voltage across the load equals the voltage across the battery, minus the voltage drop across the wire, minus the voltage drop across the car body.
If the battery voltage is exactly 12.0V, then in the "negative earth" case the voltages at the terminals of a moderate load (measured with respect to the '-' terminal of the battery) might be +11.5V and +0.1V, and in the "positive earth" case they'd be +11.9V and +0.5V.
In both cases, the voltage across the load is 11.4V. This figure is exactly the same, regardless of which part of the loop is formed by the car body and which part of the loop is formed by the wire.
because the bean counters didn't care, they were only concerned with consensus of the scientific community
I've never once heard of any case in which bean counters know, or care, about the consensus of the scientific community.
then the source of the power (Electrons)
Noooooo!!!!
Electrons are not the source of any power; the chemical reaction in the battery is.
In the late sixties, the Hole Theory started to gain some acceptance as a "Out of the Box" way to explain certain things in a different way that some found easier to understand, without getting too deep into the physics
For what it's worth, a 'hole' isn't quite the same thing as the absence of en electron. In a semiconductor, a 'hole' is (specifically) the absence of an electron in one of the inner orbits around the nucleus; electrons in this band are more tightly bound to the nucleus than the 'free' electrons which carry current more like those in a metallic conductor.
The different energy levels are important. Conduction by holes is less efficient because of that tighter binding between electrons and nuclei in the inner orbits; it takes more energy to strip an electron from its nucleus. This is why P-channel transistors are generally inferior to their N-channel counterparts.
Under the right conditions (which are to do with the respective energy levels of electrons and holes, and the 'band gap' of the material in question), electrons and holes can recombine, and the energy which was originally put into the electron to strip it from its nucleus is released in the form of a photon of light. This is how an LED works.
Conduction by holes doesn't happen in metals, though. They're a semiconductor phenomenon.