Sure it was, what makes you think otherwise?

Modern slavery still exists…

Slaves are inefficient. Actual workers generate more money for their boss.

I think you’d have to be specific about the type of slavery and the type of work they are doing.

Chattel slavery of the American South was inefficient because they didn’t modernize their agricultural process, and the Trans Atlantic slave routes were not functioning as they used too. Making it so that plantation owners had to set a new infrastructure to support and maintain their slave population.

However other forms of slavery have been and currently are still highly profitable.

There is a reason slavery is so small today compared to 200 years ago despite the much higher wages.

An estimated 50 million people are currently enslaved, in 1820 there was an estimated 40 million people enslaved.