Why is vestigial structures not removed by natural selection?

Vestigial structures are remnants of organs or traits that served a purpose in an organism's ancestors but have lost their original function. Natural selection does not necessarily remove these structures because they may not significantly impact an organism's survival or reproductive success. Additionally, if vestigial traits do not impose a substantial disadvantage, they can persist in the population. Over time, these structures may remain due to genetic drift or because their costs are outweighed by other beneficial traits.