"Under Cox, Facebook found a way to make advertising work on its smartphone app, and came up with video ads that play automatically."
That sort of jives with this anecdote as well:
"When the company redesigned the News Feed in 2013, it looked great on the iMacs in Facebook’s headquarters but made the product harder to use everywhere else."
Most computers aren't macs, let alone iMacs. How could you possibly miss out on testing for even one other thing? It's weirdly close-minded given what facebook is and how it presents itself.