I've spoken to the dev team, and this tool scrapes Steam for any content that has an app ID. Something that has an app ID is not necessarily something that will be sold. As one example, when we do a pre-order item it has to be granted an app ID even if it's never put on sale. I'm not saying you guys can't look at this stuff and speculate, but you need to know that this is not some sort of holy grail when it comes to pre-anticipating things.
This being said, we know that there are items that people want to purchase, that they currently can't. It's something we're looking into