Many unions used to administer and provide healthcare to members, before the Great Depression and WWII; but union-sourced healthcare is now heavily disadvantage

Many unions used to administer and provide healthcare to members, before the Great Depression and WWII; but union-sourced healthcare is now heavily disadvantaged from a tax perspective. I say 'healthcare' because there were many non-insurance arrangements. In some ways, having a union provide healthcare makes more sense than having the employer do it. In industries with many small firms, and fewer large unions (like construction), the union will probably have better bargaining power. Members of a given union also probably have more (means and needs) in common with each other than employees of a given company.