My daughter's LBS-mechanic boyfriend told me that Trek is having a serious shortage problem with one of their types of carbon fibon (I don't remember which type). This has been the cause of a lot of the delays. Most shops get an intial order from Trek with a variety of models and sizes and after that they order what they need.

Because of this system some shops may have a bike in stock (from their intial shipment) that now has a wait time when ordered. I guess they must have encountered the shortage after pumping out their beginning of the season bikes.