Using a razor

Hello Rabbi,
I know the halakha. The question is why – after all, the origin of the prohibition is in an obscene, primitive custom that involved bodily injury and belonged to barbaric behavior and one that sees value in the mutilation of the body.
Today, however, shaving with a knife is the most normative and standardized action. It is a gentle and clean action that aims to beautify the person.
Shouldn’t there be a change accordingly?