[Sapientoni]

I had several training seminars on bearings and was a "predictive maintenance" technician, primarily predicting when printing press bearings were nearing failure (wear out). I used computer vibration tracking equipment, but found quickly that an electronic stethoscope and common hearing could easily do the same analysis. Conrad (ball) bearings wear out due to material fatigue, not due to lack of lubrication. Steel balls are actually flexing a tiny bit under pressure much like a basketball if you push on it while rolling on the floor. Eventually, the metal can't return to the round smooth shape and tiny pieces flake off. This is called spalling. Once it begins, it will just get worse. If you examine a failed IMS bearing, and I have, one side (the pressure bearing side) of the inner race will be rough as that is the area of failure. The balls will all be rough and the balls wear out the ball cage which results in catastrophic failure.
Query me this, if oil gets by the seals and washes the grease out as many people have theorized, why would the oil stop getting inside the bearing after the grease is gone?
I think the factory would have used a different type bearing if they thought it would have lasted longer than the ball bearing. In this engine design, the pressure is always on one side of the inner race or shaft. A con rod or main bearing has the pressure around the full circumference of the oil coated shaft and the pressure is not constantly on one spot. I'm waiting to see the long term service of the "eternal fixes" some of the shops are selling.