Earlier quoted context omitted.
It doesn’t seem at all weird to me that paintings have completely different standards than films. Using a ghost painter does seem a little like cheating, if the painting is sold as being the creative and manual work of the named painter. It seems slightly dishonest to advertise it and talk about it as the creative manual work of one person, but create it using other people. I mean, I’m sure it really does happen and…
I wonder whether a (legal? social?) requirement for a full "credits" on any painting involving more than one person would change things.
This is somewhat common in other arts too, maybe more common than with painting. I know Stradivarius didn’t make his own violins, but had hoards of apprentices doing the work, almost like a company. Architecture is labeled a fine art, and gets a special exception there, but everyone knows the architect is the director of other people who labor.