Technology helped the North get rid of its slaves first - and ALL the North had slaves. But it was way harder to effectively technologize the fields of the South. Reapers, harvesters and combines finally gave technological parity to the the South with the industrial North, and enabled economic survival without slaves.
The slave issue was, of course, huge. But it was still a cover for the Civil War. That war was about the federalization of the country. Lincoln freed no slaves - he actually acknowledged them as federal property under the 14th Amendment. Then he went on to give all Americans the same “freedom,” and most people are clueless as to this status even today.
If more conservatives studied this issue, the Right would finally find the actual legal leverage it needs to stop the Left. Because EVERYTHING the Left does is through 14th Amendment status - all of it.
Would have really been hard for Abraham Lincoln to acknowledge them as Federal property. Lincoln died April 15, 1865, the Fourteenth Amendment was not ratified until 9 July 1868