I agree with most of that BUT main dealers also stand by the work no matter what so if they mess it up or it fails they will usually replace free of charge. Many independents will not give you a 12 month warranty so if they stuff it up at best you might get a 3-6 month warranty from them.Just lol if you think that it being done by a main dealer has any bearing on whether it's been done well or not.
As evidenced by the guy 3 posts up from you who was servicing cars unsupervised at the age of 16 at a main dealer.
You're not paying the extra for the expertise. You're paying the extra for the incredibly expensive stainless steel and glass showroom the service bay is attached to.