Threaded lens caps

Why do people worry about losing their lens caps when they are taking photos? Pocket technology has been around a long time. Rather, it's when the camera is in the bag you should be concerned about misplacing the lenscap. Squeeze style lens caps clip easily clip onto a lens when not in use, but on the other hand squeeze caps easily clip off when the lens is at your side or in a bag. Surely in this modern age we can do better? Hence the screw-on lens cap. They stay securely on when they should an