Ray, you are usually pretty much on target, but in this case, I have a "cavet." Dealers do have access to more specific information on there cars. No dispute. But, nothing beats a savvy mechanic, and it is hit and miss if your local Toyota dealer has good mechanics or not. Same to be said for your local independent garage.
Locally, our Toyota is just so-so. They lose their best mechanics (maybe it's the local management) and have a crop of not-so-seasoned guys who try, but tend to miss the mark an awful lot.
A few years ago, I took in my 84 Tercel for repair, they had a devil of a time with it and finally gave up. One of the comments was that it was tough to diagnose "because it doesn't have a computer."
A local indy shop had it in and out in a couple of hours. So, I do think it may depend on the actual dealership. Also, if the dealer stocks Bridgestones and Yokos, he may be trying to sell those, rather than a brand he does not stock.