"Lichtenstein: creator or copycat?"

Thought-provoking article in The Boston Globe about Roy Lichtenstein's appropriation of comic book art.

I, much like the article's author,

"never thought Lichtenstein's work was a direct copy of scenes from comic books. I assumed that he stylized certain scenes suggested by the comic vernacular of the 1950s and 1960s."
But this guy (high school art teacher David Barsalou) knew otherwise:

He has found and catalogued almost every comic book panel later blown up and sold for megabucks by 1960s Op Art icon Roy Lichtenstein. So far, Barsalou has about 140....
"He tried to make it seem as though he was making major compositional changes in his work, but he wasn't," says Barsalou, who teaches at the High School of Commerce in Springfield. "The critics are of one mind that he made major changes, but if you look at the work, he copied them almost verbatim. Only a few were original."
Case in point:

Which of course brings up all kinds of thorny copyright issues--copyright issues that the original comic book authors truly have a vested interest in.

Barsalou correctly points that musicians who "sample" other artists' music have to pay them royalties. Does the Lichtenstein estate owe compensation to the creators of the original work?
Yikes...interesting food for thought there. Any comments from the lawyers and lawyers-in-training in the house?