The dealership does have one advantage. If you need a part same day, then the dealership is the way to go. That is, unless they don't stock it same day. Or if they are closed on a weekend. Or, perhaps one bought an unsupported piece of equipment.
A few years ago I went to the IH dealership to get some guide bearings for the feeder of an ancient baler. I was impressed that they carried them. I think they were about $20 each. However, they were just plain sealed bearings, and if I knew which ones, the local bearing store would also have had them for a fraction of the price.
Right now I'm working on an older New Holland Baler, and I'm trying to decide how much will come from the dealer. I'm not ready to drop a few thousand for knotters.