I believe there's a modern (GM?) truck out there that has a belt rated for something like 250K miles...but when you have to replace it, the entire engine needs to be removed.
If anyone here owns a car with that system I recommend taking it to your trusted mechanic and discussing with them to do additional preventive maintenance on it.
What cars use those?
They aren't even trying to hide the whole planned-obsolescence thing at this point. Average age of cars on the road is approaching 13 years now, so someone who buys a Duramax-based vehicle will end up with a metal and plastic brick that costs more to maintain than it's worth, just because of the timing belt alone.
Source: I own one of these engines and I dread having to pay ~3k for this maintenance in 3 years. I like the engine, just not this maintenance ticket item.