You're talking different fields completely. Watchmen is the one comic we can all say is technically amazing. A story which is known as better than anything else.
Look at Star Wars, Dark Knight Returns, The Phoenix Saga and Indiana Jones as franchises which have lost a lot of luster after their original stories were tampered with.
This was a book which purposely didn't set up for a sequel or prequel. All the prequel stuff is already there in the preview. This is a literacy travesty, and we're all accepting of it because a company wants to make money.
BTW - Hamlet and Pride and Prejudices sequels? You're reaching.
DO you ever tire of being wrong?
Indiana Jones and the Last Crusade was a great movie. Again, that wasn't a franchise that was meant to end. When you look at Watchmen, what is there really to tell? The story ended, and quite well at that.
The Dark Knight Returns ended as well. It should never have been continued. In fact the whole point of the book is that he has outgrown Batman and learns to let it go. By going back and turning him into Batman again, well that's why the sequel fails.
There are properties that are tailor made for continuation, and there are those that should be left alone. Like Highlander...