I've spent years in and out of dealerships and honestly it depends on the detailer. Some are high school aged kids who could give a crap less what the end result is, and others are experienced guys who really do a good job, but get a bad reputation because of the hacks. The biggest problem in dealership is lack of training. Some places are pickier than others about who they hire, but you have to understand that this is an $8.50 an hour position at most dealerships. Low man on the totem pole. Many places only have a "wash boy" to maintain the inventory, and send all of their trade ins and auction cars out to a local detail shop to have the initial detail done.
As for training, most of them say "Here's the soap, here's the water hose and bucket, and here is where you park them when your done. Good luck". I don't think any of the dealer detailers mean to do a bad job or even realize they are, because nobody has ever showed them differently. 90% of the guys I've trained over the years could gut interiors, wetsand, do paint chip repairs correctly, and safely operate both a DA and a rotary within a fairly short period of time because thats how they were trained from day one.