The transitions were sudden and due of violence, and culturally disruptive
Let's take a look at some command economies: today: North Korea
In the past: The Soviet Union.
We can see that in both cases the countries failed to provide enough food and supplies for their citizens, so one way that command economies influence the citizens of the countries that had them was by inducing hunger. (the same is not true of mixed economies, or not always true).
There were many reasons. For starters, it involved getting rid of a large number of Native Americans, and while some supported this, others opposed it as they were peaceful. Another thing was that this meant the introduction of new states and it deepened the division based on whether the states should be slave states or non-slave states. Also they involved war with Mexico and some wanted this and some didn't.
<span>Harriet Tubman's primary role in the effort to abolish slavery was that he established the "Underground Railroad" (not an actual railroad), which helped slaves escape from the South to freedom. </span>