The Longevity of Slavery

I am reading an account of American history written by a history professor named Larry Schwiekhart. He openly contests some of the mainstream history being taught in our schools and wrote this book to counter them. He had this to say about the 'peculiar institution'--slavery:

He asserts that slavery lasted as long as it did in America because it was insulated by the hand of government. Had the government acted in a 'nuetral' way instead of in the protective way it did, market principles would have forced slavery out much sooner as in other parts of the world.

Slavery was not as cost effective as other industrial methods that had been or were being developed. This factor, in other places in the world, naturally ended slavery. But because of various laws implented by legislatures (that spread the costs of slavery in the South throughout the general population and prevented blacks from elevating themselves in society) that natural decay did not occur in the US. Such laws included:

Laws forcing whites to join posses to recapture runaway slaves-even if they didnt' own any.
Laws forbiding slaves from owning property or getting an education.
Laws prohibiting slaves from purchasing their own freedom.
Laws prohibiting slaves from testifying in court.
Laws restricting the movement of free blacks who lived in/or visited the south.

All these laws "emanated from the government, not the market....slave holders benefited from monumental reductions in the cost of slavery by, as economists would say, externalizing the costs to nonslaveowners". Whether they liked it or not, everyone was subsidizing slavery.

The natural "emancipating powers could work only where the government served as a neutral referee instead of a hired gun working for the slave owner."