Wisdom teeth usually develop between the age of 17 and 25 years. Some people have one,two,three or four while others have none at all. Lack of wisdom tooth might be as a result of dental abnormality. Also, you'll find that the tooth has grown but it lacks space to penetrate through other teeth but it's there only that it's not visible. For those that have visible wisdom teeth might have experienced some pain when they were growing because the force with which they penetrate between the teeth.
Final reason why some people lack wisdom teeth could be traced back to evolution. Wisdom teeth are classified as vestigial parts of the human body because we no longer use them like our ancestors who used to use them in eating raw food. Also, unlike our ancestors, the lower jaw is smaller to allow penetration of the wisdom teeth.