Would the writings of Terry Pratchett be of at least equal quality to say, the majority of Shakespeare's plays, Homer's epics, Dante's Divine Comedy, or Tolkien's Legendarium? Also, feel free to add other works to this list of Greats. What I suppose I'm getting at, is Pratchett a member of the greatest writers of all time (or at least scince 5000 B.C.E)?
I think he is easily funnier than Shakespeare's comedies, yes. And I'd put him at about the same level of satire as Dante, except likely to date a little slower (less dependence on actual named real life characters, and more making fun of human archetypes). But that's the thing about humour: it is extremely dependent on contemporary culture. Which is why I pointed out that the vast bulk of humanity would not find him (or Shakespeare) particularly relevant.
As to the others, they can't really be compared, since they aren't the same genre.
There is a world of imagination
Deep in the corners of your mind
Where reality is an intruder
And myth and legend thrive
Originally Posted by The Giant
But really, the important lesson here is this: Rather than making assumptions that don't fit with the text and then complaining about the text being wrong, why not just choose different assumptions that DO fit with the text?