Why do some people not get their wisdom teeth taken out?

Wisdom Teeth: Historically speaking, our jaws have decreased in size over the past thousands of years... for most people there's just not enough room for those teeth and they cause problems including pain and infection. For some, there is enough room and no further treatment is indicated.

Wisdom teeth: If there is enough room and the wisdom teeth erupt fully into good occlusion, and there is no impediment to good oral hygiene, there's no reason to remove them. If crowded, malposed, partially or completely impacted, have cavities, or the presence of gum disease, removal is prudent to prevent the risk of further damage.