Real world issues
You know there are valid reasons pages get junked from websites.
Given the number of photographs I've had copyright abused over the years I wouldn't be happy if some of the dead links ressurected images I've had ISP remove from the archives.
What about articles that went to be considered libellous and were taken down? Given how lazy people are there must still be hundereds of broken links/bookmarks cached and never updated, even on legitimate sites...