General strikes are difficult to start and hard to maintain. There are reasons for this. A general strike is a strike of all unions in an industry in a given area. This includes unions with skilled and unskilled workers. There are times that the demands or needs are very different for skilled workers and unskilled workers. To get everybody to agree on why a strike is needed is a very difficult thing to do.
It also is hard to maintain a general strike for a period of time. Workers have different levels of tolerance for how long they can survive without pay. Some workers are able to hold out longer than others. Once some workers decide to return to work, the general strike is less effective. Also, depending on which workers are striking, there may be incredible pressure to return to work. If strikers include workers that are striking illegally, they may lose their jobs with a long strike. The same may be true for workers with unskilled jobs. It is easier to replace unskilled workers than skilled workers. Therefore, general strikes are hard to start and hard to maintain.