My point, ultimately, is grounding things doesn't necessarily make them safer, much as ungrounded things doesn't necessarily make them dangerous.
One of the problems grounding the metal frames of residential lighting and appliances was supposed to address is Residual Current Leakage (RCD) or 'ground fault' conditions where a metal housing could be elevated to a voltage where touching it with wet hands could result in more than the amount of 'let go' current running thru a person.
In Europe and Japan they have more types of grounding systems than Canada & the US. But no matter what system they use they all employ RCD detection in all the branch circuit breakers.
Given the RCD thresholds being equal in both systems there may not be much difference between grounded and ungrounded systems.
With 'standard' US and Canadian breakers that have no RCD protection a grounded system would be safer, as that offers a default RCD level thru the equipment grounding wire only.
For example if you have say a 5ma/25/ms RCD protection (AKA GFCI) gounded and ungrounded systems are the same and I think a 2-prong NEMA 1- or 2- receptacles would be just as safe as 5- and 6-
