Oh, you're right, the number may refer to first tier only (however there is nothing interesting in 1st tier, so let's hope most of purchases are for the whole bundle;).
Anyway, thanks a lot for sharing the details. It's really interesting. It looks that the market is extremely inflated and there are no changes for reasonable profit being in "long tail". To earn something, it is necessary to be AAA dev or find the niche. This case confirms that, I think.
By the way, I was planning a bit similar project 1-2y ago as a potentialy profitable way of gaining some coding skills. The idea was to hire someone for graphics - and take a niche approach. As I have kids and I think there is still lack of decent apps for them, I was planning to make simple apps for small children (and test them on my kids:). There was also option to make them a bit catholic-friendly or even bible-themed, which I considered a chance to get attention of catholic media and get some promotion for free ;)
Unfortunately, since I've become father of three, my spare time resources completely depleted and there is no chance for that in reasonable future. Feel free to use that ideas ;)
By the way - do you consider Goldmine as the first and the last try? or planning to develop something more in future?