I think that it's particularly difficult to write about why a company failed. Theranos is an extreme example, because the root cause of the company's failure is pretty clear and because there's a lot of mindshare and commentary about their issues. For many other companies, failure is a culmination of many different issues, many of which are likely to be private. As a result, unless someone with good internal insight into the failure of the company makes a public post, a la Shyp founder Kevin [1], there likely isn't one comprehensive single cause of failure, and any speculation would likely be doing a disservice to the company.

[1] https://www.linkedin.com/pulse/i-cant-wait-you-see-what-we-d...