Back in the early sixties, our 'authorities' detected a large increase in defect reports for cracked engine mounts. After much research, they put it down to pilots using high power and very tight taxi turns, which put extremely large gyroscopic loads on the engine mounts that they hadn't really been designed to handle.
I don't recall if there was any reference to metal props and toe brakes becoming more common at that time, but both those features wouldn't help.
More grist for the mill......