Whoa...you obviously know your US slave history. But, for the sake of clarity, in NY State it was still legal to own slaves until 1821, based on the laws passed in the late 1700s.
It's even a little complicated than that, with a succession of different laws gradually emancipating the slaves. There was some compensation for a while, and different cut-offs for year of birth. The last slaves, in fact, weren't emancipated in New York until 1827, but the slave trade, the legal buying and selling, was outlawed. Of course, after that, and seeing the writing on the wall, slaveowning New Yorkers smuggled their slaves south and sold them for more money than they were going to get through compensation.
All in all, there was plenty of bad behavior to go around, but the original point, that slavery was far from a dying institution and was, in fact, becoming increasingly profitable, still stands.