> Right, and in the very beginning, only some single-digit percent of the people living in the US were eligible to vote. Women, slaves, non-landowners, etc. did not have the right to vote.

Slaves would not have been a large proportion of the country as a whole--about 20% at their height. While the early US did require landownership for adult free males to vote, the US also had unusually high landownership rates. It's estimated that ~60% of free adult males had the right to vote (contemporary Britain had about 15-20% of free adult males having that same rate). So ultimately you end up with about 25% of the current franchise rate, or somewhere in the mid-high teens after taking into account the existence of children who still cannot vote.

The US was more democratic after the revolution than before. Since then the trend has been in that direction, largely because those kinds of principles are baked into the constitution.