Different tires. The tires on your Passat were probably MXV4+, the tires on your ES are MXV4 S8, the S8s seem to be shorter lived. The tires on your Passat may have been H rated too, the ones on your Lexus are V rated.
Michelin has already replaced the S8s with the Primacy MXV4 tire, so soon after their launch I'm sure treadlife is a reason why.
People have been complaining about tire wear on these cars forever, they ship with soft rubber quiet tires which are a bummer for tire life. Has nothing to do with the car.