I talked with a new bunkhouse gasser MH owner this past summer that wore out the outside edges of his front tires in 10,000 miles. The toe in was 1.5 inches out from the factory and the dealer was hassling him for not having an alignment done after he purchased the new motorhome.
You can check the toe in yourself with a tape measure from the inside edges of the tires, measuring front and back. Michelin's are noted for their longer tread life but they are also noted for serious cracks long before they should have aged out.