Thanks for the info and the link. I'd say the cone on the right is badly fatigued. When a bearing surface wears out (due to fatigue, a result of repeated loading and unloading which is what happens to a bearing going round and round; fatigue is a cumulative effect of load magnitude and number of cycles), cracks occur first under the surface, then grow until an entire chunk of material flakes off, leaving a pit. The pits will increase in size and merge, the end result is more or less catastrophic, as far as the bearing function is concerned.