Man is born free, and everywhere he is in chains.
Jean-Jacques Rousseau, The Social Contract, p. 1

I disagree with Rousseau.

Most of the history of mankind man hasn’t been born free.  When we look back on all of human history, until just very recently, the person at the top of society told the rest what to do.  Its only very recently that the common citizen began dictating his demands to the government.

Why the change?

Modern man (from a biological standpoint) came into existence about 200,000 years ago.  But historians seem to think that it was 50,000 years ago that man began behaving modernly (had developed culture, writing, etc).  Then some 8,000 years ago we learned how to plant crops which started us down the road to a sedentary lifestyle.  Now a bunch of us could live in a relatively small space instead of having to wander all over creation.  Here’s an abbreviated summary of where we’ve been:

Its only in the last couple hundred years that people actually became free; most people; the average man.  That’s just an eye-drop in the lake of time when you think about 50,000 year of human history.  The tiny ruling class of past societies (whether they were the government rulers or the clergy) have always been relatively unconstrained to do what they wanted, but not the average person.  Until recently.

This change was caused by the rise of capitalism.  Until free markets emerged the common man was the serf, the peasant, the slave.  BUT under capitalism he became the boss:

[In] a capitalistic society the common man is the sovereign consumer whose buying or abstention from buying ultimately determines what should be produced and in what quantity and quality.
~ Ludwig von Mises, The Anti-Capitalistic Mentality, p. 1

This was, from my examination, the turning point.  No longer were the masses treated like they were too stupid to know what was “best”.  No longer did they need a noble, or a chief, or a priest or some other totalitarian figure to tell them what they needed.  It was that taste of freedom that has propelled mankind forward.  The power of hundreds of millions of people finally free to each pursue their own individual self interests as they see fit.  And with that taste of economic freedom mankind demanded he be given his other civil liberties to go along with the first civil liberty he ever gained: economic independence.