We're built to just last long enough to procreate because that's been the optimal way to keep our species alive. Regenerating causes issues (cancer, malformatio

We're built to just last long enough to procreate because that's been the optimal way to keep our species alive. Regenerating causes issues (cancer, malformations, takes energy), so if the body can build it only once and last 20-30 years, it's optimal.