And in our world in of "cornering", "compliance" is usually the last thing we want, hence the compromise. Also, urethane even when available in different durometers, is still not thought to be compliant, and if forced to be compliant, I suspect its lifespan is greatly reduced, as the OP maybe finding out. Rubber, and rubber bushings that are larger then expected, and sometimes with holes cast in, is the direction compliance is normally found when needed, where lifespan is sought, such as OEM solutions.