I read it also....pretty amazing.
The 5.3 in my silverado has only 150,000 miles on it.It's a 2000 model.
But it has just over 6000 hours on it...

and only a water pump replacement 2 years ago.
I used to tow my boat for years every weekend and spend alot of time idling at the job sites with the AC on,and still do.
The trucks have an hour meter if you push the trip odometer switch when the ignition is off.
Wish the Camaro had one,a much better indicator of engine age and use.
The LS engine really is an enginering marval.