Most failed startups fit into the following timeline: was burning more money than it was making => failed at raising more money => did a round of layoffs / cost cuts to get economics under control => couldn't right the ship and shut down / did a fire sale or acquihire
But, the above timeline doesn't teach you much about why the company really failed. The real answer almost always involves a multitude of contributing factors, and requires intimate knowledge of the startup's business.
For the most part, the only reliable source for this type of information is one of the founders, board members, or (sometimes but not always) c-level execs. And, even then, they have to be willing to be vulnerable (which is very rare).
If I could give some advice to Failory, it would be to think about how you can incentivize founders to share their stories. As it stands, they have little to gain and potentially a lot to lose (e.g. being labeled one of YC's "biggest failures")