Because they wouldn't win and that would set a bad global precedent for them. They won't win in Japan or Germany either, but they have a chance in South Korea.

Because they wouldn't win and that would set a bad global precedent for them. They won't win in Japan or Germany either, but they have a chance in South Korea. South Korea is part of WIPO, so a favorable ruling there could pave the way for an actual filing in the US. But anyway, it won't come to that. Apple could own Samsung (and every other Android manufacturer out there) several times over with their patents and design marks. The Galaxy S is a blatant knock-off, which is why Apple got pissed. But... whatever. They'll settle, with Apple getting a nice discount on Samsung Semi and Samsung changing the design of the Galaxy line. Not a big deal. The end.