Earlier quoted context omitted.
What typically happens with unions is the agreement will likely contain a salary guideline adhered to most of the time, which diminishes individual leverage.
The unions you are referring to are almost universally for blue collar workers. Most professional athletes are members of unions. Most highly paid actors are members of a union. Neither of those groups have decreased individual leverage. It's unlikely that a union for highly paid white collar workers would closely resemble a union for blue collar workers.
Huh? Sure they do. The MLB negotiated agreement is terrible for top performers, who are paid close to the league minimum salary for the first three years of their career, and an arbitration-determined salary for the next two.
As soon as the union-negotiated common salary time runs out, top players’ pay jumps several times.