why did the resistance movement wait so long act?

Any resistance movement was difficult in a Nazi concentration camp. The resistance was made up of people who were political prisoners, some Jews who had been able to pass for non-Jews and people who tried to undermine order in the camps. It was very difficult for all these people to gel. The Nazi camps worked well at de-humanizing people until they felt nothing. When everything is stripped away, prisoners in the in the camp begin to betray one another until there is simply nobody to come together. It isn't until late in the book when rumours of allied liberation spread that the resistance believe that there is hope and something to fight for. Finally their captors look weak as they have lost the war.