That takes like 10 years to happen though. I live in salty snowy Canada and I very rarely see rust on any vehicles here that are less than a decade old (vehicles period, not just trucks). The only exceptions I see to that are normally poorly maintained and beat up company vans, pickups and cargo trucks.
Also when a chrome bumper does eventually go, you can swap them out easy peasie for about $200 buying from a local yard or off someone on kijiji. My wife always gets my hand-me-down when I buy every 5 years so our 2nd vehicle stays here for 10 years. In 25 years of being together, only one of them got a wee bit of noticeable rust on it and that was a cheap old budget chevy we had in the mid 90's. She's driving a 2008 Accord right now, not a speck of rust on it. Lots of paint chips on the front bumper though!