Bearings are case hardened and polish ground to the exact surface dimensions needed for the application. There are two main bearing failure modes. The first is simply due to wear over time. This wear is normally due to microscopic particles in the oil, wearing the hardened surface off.
The second type of failure is due to overload. In overload situations, the case hardening can literally peel off softer base metal, due the the constant high pressure on the bearing surface. This high pressure will de-laminate the case hardening off the base material. This is the most common failure mode for the IRD bearings.
Does that match the photos above? To me, they look more like damage from metal particles in the photos that appear in the articles shown in the links. Maybe a combination of the two? Maybe just general wear and tear (150,000 is a reasonable innings, I guess?) so that the case hardening is thinned to almost nothing, and then the metal particles in the oil have pierced what's left of it in various places?