I've got enough pathology of Ungulates under my belt to know abnomal wear, and that is a shear mouth. I've done too much corrective floating and sx. All animals wear, but not to that degree. The visible root on the outside of the tooth is all you have to see with abnormal wear. If your seeing all old deer with a sheer mouth, then you have some abnormal deer. Teeth wear from the top down. If their wearing on their sides, as in the outside is here, they are getting abnormal wear. Even the teeth from back to front have very different wear angles. No doubt that is a very old deer.
A more normal 9.5 yr olds mouth>
Notice the roots are not visible from the outside.
A bunch of pointed tips on cheek teeth are indicative of a younger animal. WIth the shears, this may be difficult to determine, but I'd say the 5.5 yr animal here;
may show a more similar pattern to the hind cheek teeth with points.
More simply put, his bite was abnormal, and gave him abnormal wear. I totally agree about the sand speeding things up. pasture fed animals wear much faster than grain fed.