Maybe dealers have a quota on the number of warranty repairs from Toyota and it looks bad if they take in too much warranty work?
As posted...I believe it comes down to money and ego.
Also posted...a smaller dealership...or one in a smaller community with less service volume, will be more agreeable to do the TSB because it's a pay day for the service dept. part of the dealership...
Whereas, a large volume dealership that has folks lined up for retail service work...may be less cooperative to do the lesser paying TSB or warranty work.