Despite the ludicrous funding for Starliner, press, spaceflight fans, and NASA alike want to know the cause of delays. Leading the investigation, was NASA Official Staspar Canley, who had these findings on the subject.
"Our main objective with this investigation was to find the root cause of the delays that have been plaguing Boeings Commercial Crew contract. The root cause of delays was discovered to be the USPS. Boeing has been shipping parts, data, and even entire capsules with USPS. And even worse, they have been selecting the slowest shipping method to save money!
Staspar Canley went on to explain that over the course of the contract, the USPS has been slow to deliver, causing massive delays for Boeing. In one case, the USPS entirely lost a flight ready Starliner that was set to fly the first crew, with it's whereabouts still unknown.
The fix for this seems obvious, they could simply ship with Fed-Ex like ULA, or UPS like SpaceX does. An anonymous Boeing source however says that they prefer USPS for the low rates. They explained that they get discounts with shipping capsules by simply strapping it on a USPS trucks roof, and ridesharing to the destination