I had a personal theory that is not backed up by anything, to me WHF earth is sort of a sandbox where old ones threw stuff to see how it worked before going full production, or before releasing "patches" for the races they created. A sort of PTR server.
Also, Dune is Sci-fi, fiction and fantasy are pretty similar, but I get you see a difference between hard sci-fi and more liberal stuff. Also, iinm navigators don't do the space folding, they only plot the course, and they wouldn't even be necessary if there wasn't a computer ban in act.