It's not the number of incidents that have occurred,it's the number of potential incidents that have yet to occur. The faulty batteries are installed in far more than 74 handsets.
Would you want one of them in your house? With your family?
As for the iPhone thing...ANY device containing a lithium polymer battery can and may explode if the battery is damaged. Any phone (iPhone aside) that contains one that is dropped, bent, or damaged in some fashion is at risk for the battery exploding. The Samsung situation is quite different - no damage is necessary to trigger it, it just happens during charging.
There's a difference between a battery that burns up because it was damaged in some way vs a battery that burns up because the owner just plugged it in to recharge it.