Man, you want to have your cake and eat it too. The immigration gains were in the northern states. Most immigrants settled in the north where the jobs and opportunities were.
The slave population was in the south. By the time of the civil war, slaves represented approximately half the population of the Deep South states. Half! Slaves had twice the birth rate of the white population. That made economic sense to the slave masters… each slave was worth a lot then, but as time went on, it would pose a major problem if they didn’t find new markets to sell the excess to.
There were immigration gains in the Southern states, just not as many. The Southern states were less industrialized and it was large factories that were really sucking in lots of labor.
The slave population was in the south. By the time of the civil war, slaves represented approximately half the population of the Deep South states. Half! Slaves had twice the birth rate of the white population.
There were some states in which slaves represented roughly half the total population. Their birth rate was not anything remotely approaching twice the birthrate of Whites. As a whole in the South, the White 1860 population was closer to twice as large as the slave population 9,103,332 people out of which 3,521,110 were enslaved.
That made economic sense to the slave masters… each slave was worth a lot then, but as time went on, it would pose a major problem if they didn’t find new markets to sell the excess to.
There wasn't any great "excess" of slaves as witnessed by their high price. Had they really needed markets to sell to there was always Brazil and Cuba which perpetually had to import more slaves because their death rates were so high. This whole theory of them needing new markets to sell excess slaves to is bunk. Notice when they seceded they made no claim on any of the western territories of the US.