I think the “two” states would have re-united by 1905 per Winton Churchill’s book “if Lee had not won the Battle of Gettysburg”
Essay
McKinlay Kantor reached the same conclusion in his book If the South Had Won the Civil War (New York: Bantam, 1961). He figured that the US as of 1961 would have looked pretty much the same except that Cuba would be a US territory and Alaska would belong to the Soviet Union.