Maybe. Most automotive engines ran just fine for a normal lifespan without changing the valve seats. When you work the engine hard you need it, but if you are not racing you generally got by with it. Of course the change for automotive was the early 1980s when engines were not as reliable and didn't last as long.

Don't forget that aviation engines are require a lot of regular rebuilds. In a car you wait until something breaks, in an airplane you replace parts long before they might fail to ensure it doesn't break when in the air. So for many we can just add replace the seats/valves in the next tear down and be okay.

Practically all aviation engines have used hardened valve seats since even before WWII. Maybe some WWI era engines didn't have them, I'm not sure.