Two notes:
1. Linux kernel doesn't have any 'copyright assignment' policy. This means that Linus CANNOT change the license of Linux kernel by himself. All kernel contributors should agree with it! Therefore, it's practically impossible to change the license of Linux kernel. Its license doesn't include 'or any later version' clause, so nobody can change the license to v3.
2. Hurd doesn't take off, becuase its development was soooooooooo slow. It still has no stable version. So, its license is irrelevant.