A timing chain (not timing "belt) is designed to last the life of the vehicle. Oil maintenance of a car with a timing chain is an absolute must, but the chain isn’t routinely replaced… if ever. So a 10 year life-span is pretty crap, if the oil changes were maintained. Even 120k miles puts a 10 year car at 1,000 miles per month, which is relatively heavy usage.
I assume the genesis 120k replacement has more to do with the nylon guides and/or shit quality, if that’s the recommendation