There are many different reasons why the contributions of women to the history of the Revolutionary era have been relatively under-represented in historical writing. The two major contributory factors are the nature of the historical record and the biases and disciplinary frames of historians.
In terms of the historical record, men had a far higher rate of literacy than women of the period, and were far more likely to hold positions of power. Thus if one is writing a history of presidents of the United States or of generals in the Revolutionary War, one's subjects will necessarily be masculine. Because men had a literacy rate several times higher than that of women, any representative discussion of writings of the period will contain proportionally more writings by men.
Two types of historiographic bias have also contributed to the marginalization of women's voices. The first is the "great man" tradition of history, which constructs historical narratives around the most prominent and powerful people and events, which were, in this period, dominated by men. More recent types of "history from the bottom" try to rectify this bias. The second bias is that well through the mid-twentieth century, most historians were men, living in a strongly patriarchal environment, and tended to view history as the history of other men.