Actually, between 50 to 75% of the English, Irish and Scots who came to the Americas between 1500 and 1750 came as indentured servants, which is a form of slavery. People seem to forget that slavery was a world-wide institution at the time, not an American invention limited to Africans.
The mass importation of Africans didn't occur until Eli Whiney invented the cotten gin and made production of cotten more cost effective and less labor intensive, by eliminating the need to pick the seeds from the cotten bolls by hand, which was too time consuming. The ability to more easily and cheaply produce cotten created a market for mass labor to pick the cotten, and the grand plantations with all the African slaves were the result.
OK, so hindsight is 20-20. But I'll bet if they'd realized what a mess they were creating for their descendents, they would have picked their own damn cotten!
The English, Irish and Scots who were descended from bonded servants would have gotten over it and built this country, and the Africans would still be fighting tribal wars and selling off their captives to Arab slave traders.