Sorry, this doesn't add up. Lean doesn't mean your product breaks or is pushed out functionally incomplete. If no one wants it it's not viable.
The article says give your customers what they want. Unfortunately they thought the customers wanted a mobile app... but they didn't! Wait, what startup methodology could have prevented this...
The article is honest about their mistakes and that must have been hard to do and props for trying but don't try and pass the failure buck to a methodology you didn't even do right.