Well, you are filling a couple niches that is sorely lacking right now:
1) Jump in Gaming - Five core books and 3 Gloranthan books into RuneQuest and we have only one introductory scenario.
2) Traditional RPG setting material. Gloranthaphiles are heavily represented on this board, but there have been a lot of people who have mentiond they like the system so far, but don't want to game in Glorantha.
I would say of late you are the primary producer of RQ material for the more traditional RPG type setting. Sure the Lankhmar and the EC lines are coming, and while more traditional than Glorantha they are still niche type products. Classic Fantasy play is wide open right now as far as MRQ goes, and quality supplements will only help the market grow.
And did I mention Jump in Gaming? That one is big.
A cool cover never hurts either.