When they started putting catalytic converters in the exhaust pipes they said they would last 50,000 miles. The one in my Chevy is still working at 120,000 miles. That can gets hot, though; you can feel the heat on the floorboards if you sit in the passenger seat.
Common occurance. Have you ever had a "sniffer" on your exhaust for a license renewal? Can't pass the pollution test, don't get the renewal. Also, have you noticed any difference in fuel milage? Often, the convertor gets "saturated" ie; plugged and exhaust just passes through. With Hybrids, however, if the packs can't hold a charge, or it runs out too soon, your left with a gasser if it will run at all. Regards.