I think there are more reasons for ball dead then just oil and dirt.
I clean my equipment very well. When they lost performance, some of them I got back to react good again, others stayed dead.
I think it is also in the material itself. the additives that make the urethane proreactive vaporize in time. This happens with all plastics. My neighbor had a plastic ship model, that just crumbled at touch. Maybe that in some balls this happens to fast?
Because some people experience it and others don't with the same type of ball( maintained correctly), maybe it has to do with the consistency in quality of the raw materials.
I think, would this happen with a product other then a bowlingball, the company would get a lot more warranty claims. Now all is due to the owner or use.
When I calculate what the costs per game were for some balls I get a little irritated.
Greetings,
Antoine