One reason they don’t is because they’re afraid of ways in which a union might hurt them. For example many unions become overly political and involve in issues

One reason they don’t is because they’re afraid of ways in which a union might hurt them. For example many unions become overly political and involve in issues that aren’t just fighting for wages and benefits (like taking on social justice issues). Many unions have tenure based rules that they negotiate to privilege some workers above others. Many unions end up becoming so hostile in their view of the company, that they end up hurting the company and limiting everyone’s income instead of working together in a more balanced way. I think even now, the perception (even if it is wrong) is that all the possible negatives are worse than the possible benefits like fighting RTO policies.