Yeah over the years of traveling I've seen a number of buggered up rigs due to tire failure at hwy speed. One in BC tore up good size area of the trailer. Another tore up the fender and some trailer in front and behind the duals on the toy hauler. Also took out his plumbed in propane line located a couple feed ahead of the failed tire. Use to power his gas grill. Hope he had the propane shut off or there went a tank of propane.
Bottom line tire monitors are your friend and you can't inspect the rubber and rims enough to insure a lower chance of failure.
Several decades ago I was traveling between TOK, AK and Dawson City, YT via the Top of the World Hwy. Came across 3 rigs with flats due to a section of road at the time that was constructed of sharp edged, large shot rock. Stopped and everyone at each rig was fine and had a spare and tools to change the destroyed tire. Last summer we traveled the same road towing our previous 5er and needed to lock the hubs in and shift into 4H as we were slogging in half a foot of slick mud.
As for tire age. I change all mine on all my vehicles every 5-6 years. Seldom is the tread gone just a matter of safety.