In order to understand where is line between plagiarism and creation/inspiration exist, we have to realize that it’s totally different events. Creation is a complex  complicated process which include all levels of author beings, it’s more spiritual or intuitive than explainable or understandable. From the other side plagiarism is a technique, is something anyone can learn and being good in it, even perfect. It’s like driving car: some people doesn’t know how to do it , a lot knows how to do it good, singles knows how to do it excellent, but it’s not an art.
Even if somebody really good in compilation, it’s not make him a good artist, it’s actually make him no artist at all. Doesn’t matter what genre of art is mentioned or what stile, James Joyce, for example, through the whole first part of Ullis was doing a parody for all literature styles of all times, from Homer to Classicism, but he was not copy of anyone . Moreover, he was the first Modern writer. Same way Leo Perutz always took real time and characters but put them in mystical or even magical environment , where God and Devil play together with regular people.
Plagiarism or compilation, is an actual level where true talent never can exist, the speed is too low, the prize is too miserable. Compilation is a pragmatic people poison, when at the same time, inspiration is whine for a gifted, and unfortunately they almost never mix together.