Did OEMs wet sand and buff paint?

i will ask this question. if using single stage enamel or urethane, is not the urethane more durable? that is my belief.

back in the late 80's and 90's, I had a guy do my bodywork on cars that were getting the resto thing. he could lay down acrylic urethane or enamel, that had a great shine and look. NO sanding, buffing. NO it did not look like bc/cc. he said the secret was a very slow reducer. but then he was an expert painter too! like Pete in NH said.
runs??? yes the original cars had plenty on firewall or other such places, and yes they were not very good at putting paint on edges of inside of doors, all under the hood and trunk lid. the reason were get all warm and fuzzy looking at REAL survivors cars, is to actually see how the factory guys actually did it!!
I can remember my dad complaining back in the 60's how paint was not as good as some ?? ( how many???) made decades earlier, ....as they even back in the 60's , they were messing with the lead in paint.
he used to refer to some metal primers as "red lead", he spent 20 years in the marine avaition field, so he probably had some experience with paint in aviation and navy, having been in the Marine Corp.