There is no question that modern engines last a very long time on uber-thin oils. However, many manufacturers, including Hyundai have suffered unnecessary warranty claims due to the use of thin oils coupled with extended drain intervals. Many, possibly even most, drivers do not understand that their operations fall under the "severe" category that includes more frequent oil changes. Things like many short trips, towing, extended high speed operation (many people speed) , extended idling and so on. These things are spelled out in the owners manual, and often ignored.
It's easy to discount the sentence that states higher viscosity is required for operation in high temperatures. South Florida people continue to use 5W-20 oil in over 100 degree temps (at the road surface) , while going 90MPH down the highway, and expect good results. Then they become annoyed when the balancer chain fails, the timing chain wears out, the cam phasers knock like an old diesel engine and so on.
It's very telling when Ford requires 10W-50 in their "trak-pak" vehicles with the exact same engine as the normal version of the car (which requires 5W-20) Heat and heavy use require sufficient viscosity. Twas always so.