The Constitution was both written and ratified years after the United States won independence.
The Constitution Rev 2.0
The Declaration would not have been adopted without the South, and the South would not have signed off if slavery had been abolished then and there. The Federal Constitution was ten years later and many of the Founding Fathers were still around and still there. Patrick Henry too, although nobody listened to him anymore. Trade-off came back to bite a couple generations later and still hasn’t quieted.