I'm merely saying, even though I know the importance of JIM83, I'm not a big Thor fan so never would have considered the book. Don't we see the same happening on FF1? With SA books, Spidey is probably the biggest, and one that people demand the most. The book is also historically important.
Wolv may be a popular character, but is he historically important? GSXM1 might be more so for a bronze book, but maybe not as popular as Wolv on his own. AF15, Spidey, has both popularity and historical significance, and is older and more rare.
Again, I have no idea, I'm throwing out my own guesses.