In what ways did colonial america change over time from a “society with slaves” to a “slave society”? what is the real difference between these two concepts?

The main difference between a society with slaves to a slave society is what role the selling and use of slaves has on the economy.

The United States shifted between the two when the selling of slaves became an economic driver onto itself, instead of just a source of "free" labor.

mass production/ assembly line production

nothing certain is known about what happened, but it seems that the country declined gradually, perhaps due to bad government, or, more likely, due to a series of bad harvests, which resulted in widespread and recurrent famine.