Of course a big reason they expire is so the registrars can get money from you registering them, they aren't providing much service. A much more sensible system

Of course a big reason they expire is so the registrars can get money from you registering them, they aren't providing much service. A much more sensible system is they wouldn't expire. The domain registration industrial complex, with the zillions of dodgy groups that squat on domains is of course not providing much value to the world.