Plus Marvel Comics have teamed up with GW to make GW comics. They must have a pretty big fan base to get that done.
Got to think back when I first REALLY noticed GW – as I found the White Dwarf (German edition) in a local super market. Must be in the early/mid nineties. In fact it was the only hobby periodical to be found in local stores. That alone has given GW a headstart here back then.
Something similar happened with Battletech around 1989/1990. A large publishing house brought the Gray Death trilogy on the market and they became an instant hit – in fact the publishing house earned more with the BT novels as with the rest of their complete program for over a decade. And I think Revell´s Robotech Defender kits, which looked similar for non initiated, from the mid eighties helped a lot in this case.
"In strange grammar this one writes" - Master Yoda