I think Buddhism started as a way for people of the lower caste to cope with suffering in their life. In India, what family you were born into determines the class you are in for life. At least this was what it was not too long ago. For example, if you were born in the lowest class (untouchables), you were stuck there for life without any way for advancement. This class are made up of mostly beggars and people ignored by the main population. Other castes include teachers, merchants, priests, etc. However, because you are stuck in a class for life, certain religion were fitting for these people. Because they cannot get out of their current situation, they turn to religion to provide relief. Buddhism basically says that life is suffering (the first noble truth), and you basically need to remove "desire" to get rid of suffering. In other words, remove the "desire" to have more benefits or more status in other classes, just accept your current birth class and suffering.
There are benefits to Buddhism, however. It provides an awareness to when excessive desire is counterproductive to a person's lifestyle. However, to simply ignore the possibility to advance is difficult to imagine. How much desire can you ignore? To the point of having no desire to eat and drink and thus die? This spawned a practice of fasting in certain Buddhist sects. The awareness obtained from fasting is up to debate, but it is difficult to imagine giving up your vehicle (your body) in this world is a long term solution.
Because most of the world does have castes still (well, you can think of them as different classes of rich and poor), Buddhism seems to lets the lower class cope with suffering, and the upper class deal with over abundance of desire. However, it should not be forgotten that what brought about the influence of Buddhism in the first place... different classes and the suffering brought about by the inequality of the lower class.
