I think it would be more correct to say they fail from stress. If you took the same rod and run a lighter piston it is going to have less stress on it than a heavy piston at the same RPM and it will last longer. Also if you run a shorter stroke at the same RPM and piston weight the one with the shorter stroke will not see as much stress and will last longer. So RPM does kill them but it is more than just saying they can handle 10,000 rpm, it needs to be quantified with saying they can handle X amount of RPM with X amount of stroke and X piston weight as all threee of those are probably the biggest variables although there are others.