Suppose that a car has 120,000 miles on it and the catalytic converter fails.  From what I read ([see here as an example)][1], age doesn't appear to be a general cause for failure.  Is this a possibility if a car is old?

Note the site lists the following reasons:

-  Thermal Failures
-  Contamination
-  Coated or Fouled
-  Other in pictures:  Melted Brick: Engine running too hot, Burned Converter: Exhaust temperatures too high, Oil-Fouled Brick: Engine oil entering exhaust, Plugged Brick: Incomplete combustion by-products, Road Damage: Impact under vehicle crushing converter.

[I found this][2]; it indicates they last about 100,000 miles.