User blog comment:Trulyrandom/The Matt Ward thing./@comment-4608429-20120504222103/@comment-10514705-20120506095019

But Tardir, your forgetting the main thing which all four of the settings mentioned have in common: the ridiculous number of books and literature supporting parts of the canon/fluff.

Hell, 1/3rd of the planned 9 part SW arc Lucas had planned exists entirely in books. Then there is all the Clone Wars stuff.

Warhammer 40k has a large number of games and a movie. But the main fluff, obviously comes from books.

Star Trek, with six TV series and 11 movies provides an expansive universe. Which is then made even bigger by the massive number of books.

Doctor Who, now with more episodes than Star Trek, is also ridiculously large universe which traverses about 100 trillion+ years. A lot of additional adventures and fluff is provided, again, by books.