Why did slave owners choose Africans to enslave and why did slavery go on for so long in America??

Slave owners had choose to enslave Africans because servants were to expensive (also warfare and diseases had decimated native populations). And why it went on for long was because slave owners wanted to gain wealth for themselves and men primitive enough to keep slavery alive by feeding money into it as customers.

Is this a joke question or what, obviously that means red dead redemption 2!