The only time, in the US at least, anything has led to long term appreciable change in society for the betterment of the working class was when capitalism was in legitimate fear for survival in the face of communist revolutions the world over aside the great depression. The FDR generation didn't go from effectively total labor exploitation unbounded to 40 hour work weeks, unions, paid vacation, and safety regulations because the collective bourgeois woke up one day thinking their time had come by happenstance. Concessions were made to preserve the power structures that gave immense power to few at the cost of the many.
The civil rights movement was comparable where the most popular speaker in the country was espousing socialism and class consciousness and had to be assassinated to stop his movement adjourning organized aggression by the Black Panthers who also were mass murdered. But all that blood only managed to move the dial a hairs breadth toward liberty.
We will all be good citizens voting for one of the two choices presented us by our rulers this November, many of us going into the polls knowing the structural organization of said process means our vote is totally meaningless - first past the post, winner take all races down a scorecard of positions 90% of which you know nothing about but the letters aside the names, names you probably only heard in TV or radio ads inundating you for two months prior. Its a mockery of actual democracy and largely always has been - there is a reason the US was founded to have an electorate of white, land owning men.