P0420 and P0430 code - all four cats cooler at output as well

Looks like I have my first expensive failure in 172,000 miles. Not that bad I guess. Still drivable, just the CEL came on. I scanned. Prayed it was just the O2 sensors, but did the infared thermometer trick and noted that the exhaust was significantly cooler on the output. That is the opposite of what it should be. I'm just shocked that all four are doing this, and will test the O2 sensors and the Cats more thoroughly when I change my pads and rotors this weekend. How common is this failure? Seems I see a lot of people saying the cats fail before the sensors. Anyway 200k miles damn near, so I can't really complain.