If you think that the freedom to quit is without value bear in mind that under feudalism and into the early 19th century in the U.S. and a bit later in Britain employers and even potential employers could prevent workers from quitting and from moving. The freedom to quit was hard won. We should not disparage the liberation brought by a free market in labor.This is not in fact true. Freedom to quit, even in the early 19th century, was exercised across New England. See Jonathan Prude's Coming of Industrial Order for numerous accounts of "French Leave", or the practice of workers coming and going from the factories as they felt convenient.
Tabarrok is about 20 years behind in his research on 19th century American labor law. In a recent (2010) account, Christopher L. Tomlins convincingly demonstrates the relative lack of institutional controls on adult white male workers as far back as the 17th century. In what is a practical overturning of Steinfeld's thesis, Tomlins demonstrates the relative continuity of labor law for adult white males even through the Revolution and into the 19th century.
So the right to quit never was a key element of workers' concerns -- rather, as Tomlins suggests, it is the grafting of Master-Servant law onto employment relations in the late 18th century which represents the real significant legal change. And indeed, that set of laws was hierarchical and undemocratic.
Why is this important? Because it shows that whatever the right to exit may mean in social relations, it certainly is not the main issue and certainly does not comprise what we mean by "workplace democracy". Workplace democracy means the right to control conditions of labor, and that's something which Master-Servant law has quite clearly shown to not exist in American law.