law and labor

Why do you think the timing of labor legislation in America (beginning with the Railway Labor Act and National Labor Relations Act, and working forward) was as it was? What was happening in our country during these times economically, geo-politically, etc. that influenced this lawmaking?
Looking at the evolution of labor law since then, do you think that our modern laws do enough to address protections and support for organized labor and collective bargaining relative to other first-world countries? In other words, are we progressive in this area, or falling behind? Explain your answer.