If it were possible for one to be at an assembly plant, just as the vehicle has completed it's paint process and felt the painted surface with a baggy or the cellophane off a cigarette pack, they would feel the a basic "uneveness" in the paint film.
Just the nature of paint, it is not near as smooth as one would assume.
If one has buffed, polished, sanded and buffed, etc, that uneveness is removed, but so is an important part of the clearcoat film and the important UV blockers.
Now, if at one time the paint does feel very smooth, but later developes the "roughness" etc, that is most likely due to corossive chemicals having entered the paint film and are "swelling" the paint film.
The vehicle industry referrs to this as "industrial fallout", "lot rot", and other terms.
Everytime the paint is exposed to water and heat, those chemicals (usually sulfuric and nitric based) are breaking down the resin system of the paint and that is what/or may contribute to clearcoat failure sometime in the future.
The ABC system removes as much of these acids, etc as is possible, which is why so many of the vehicle manufacturers have issued Technical Bulletins for it's use or in some cases, even included it's use in the service manuals for their vehicles.
Grumpy