DERG
The friction produced in the Ball Bearing structure heats the oil, and higher as the wear continues. Once worn to even small amounts, the cycle begins. The vibration caused by harmonics and the damage itself makes quick work of the "Three Way Bearing??"
Will ever increasing viscosity and "Additives" be required as the Cycles advance?? Perhaps as a final "correction", the requirement of "Hypoid" grease??
One can say that the Ball Bearings do an excellent job of restraining mechanical forces. They are not meant to perform at their high level of design when encountering "Novelty". A record of Oil Temperatures v the log of thrust, time on wing, cycles, etc. Would be instructive, and rather simple to produce.