I'm not sure how widespread this issue is, for deliveries via service center -- in the Seattle case, they have something like space for 14 cars to be delivered at a time, so they can only accept shipments from the factory of up to 14 cars. If more customers than that have built cars, they get stuck in a waiting queue, or if people are slow to pick up, everyone else gets to wait behind them. That's my situation, car finished on 1/18, waiting behind other deliveries before it can even be shipped up here... still awaiting an ETA of when i'll get in the queue.
I would kind of expect Tesla to just to direct ship if they can't make their service center delivery model work. It might cost them more, but wouldn't that still fit in their delivery fee?