The SAE towing ratings are
The SAE towing ratings are ignored by the Big 3 because they know that those ratings are no more valid than the EPA fuel economy tests and ratings. If Toyota had trucks that could pull the amount of weight that the Ram 1500, Ford F150 and Silverado 1500 could - they would be publishing those figures as well. Toyota only conforms to those standards for the sake of being able to say "we are the only company who conforms to SAE standards but the buying trends make it clear that consumers dont care about that.