The biggest takeaway from this story is "The absence of a specific QA function may be hampering the company as well." QA is vital. A proper QA department sees the forest and the trees. Developers see the trees (or, in some cases, just the branches). Having proper QA means that John doesn't accidentally break something that Julie was working on, because they run regression tests. It's quite astonishing that QA isn't a separate team at Facebook for their iOS apps.