Why don´t pig farmers stop pig castration on a large scale?

Pig farmers are used to castrate their male piglets. They’ve always done it and slaughterhouses did not accept uncastrated male pigs because of the alleged risk of smell abnormalities and boar taint. Up till now, many pig farmers have not included the economic, environmental and welfare benefits in their decisions. Still, not all pig farmers are aware of and recognize the benefits of non-castration.