Better picture.
It's called cupping and that is caused by the crown in the road. Notice it's only on one side? You can up the tire pressure to decrease the cupping but it's how the road eventually trashes your tire. The dealer is right this has been happening for years. If you do high miles try using a dual or triple compound tire or use a harder "touring" compound tire. Some have mentioned Avon Storms in connection with high mileage I'd try that. Wardie