This is purely an observation from my point of view but whenever i see a study or painting based on a masterpiece or a screen plate. The results are almost in every case very good.So this tells me that our ability to copy is quite good and its not really required to be a high level artist.Junior level to mid level ones can pull this off easily too. Everything you need to know is already in the image we are trying to copy so it becomes a recipe for us.
the important thing though is to not "copy" it but to understand it and deconstruct a work method from it.And if you understand that then the work based from your own mind will be alot better.
When i see this kind of work , for me its not the level of detail and accurcy that one puts in the copied artwork that impresses me, but the images based on that learned knowledge afterwards. And to tell you the truth not many people understand this knowledge or are aware of how important it is to understand it.But the interesting phenomenon is that