[stonogo]

The Arab slave trade took more slaves than that over the course of twelve centuries. The transatlantic slave trade only existed for a few hundred years. The event that led to the slow demise of Arabian slavery, the Zanj rebellion, occurred a thousand years before transatlantic slavery even existed.

In short, the Arabian slave trade did benefit, but it was on the way out by the time the Europeans got interested in colonial slave labor. Don't make the mistake of thinking everyone in the world got involved in the slave trade then got out of it at the same time.

[nhchris]

> The event that led to the slow demise of Arabian slavery, the Zanj rebellion, occurred a thousand years before transatlantic slavery even existed.

Slow indeed:

It is estimated that, in the 17th and 18th centuries, 1.4 million slaves were compelled to make the trek through the Sahara [..] 1.2 million slaves are estimated to have been sent through the Sahara in the 19th century. In the 1830s, a period when slave trade flourished, Ghadames was handling 2,500 slaves a year. Even though the slave trade was officially abolished in Tripoli in 1853, in practice it continued until the 1890s. - https://en.wikipedia.org/wiki/Trans-Saharan_slave_trade

Robert Davis estimates that slave traders from Tunis, Algiers, and Tripoli enslaved 1 million to 1.25 million Europeans in North Africa, from the beginning of the 16th century to the middle of the 18th (these numbers do not include the European people who were enslaved by Morocco and by other raiders and traders of the Mediterranean Sea coast). - https://en.wikipedia.org/wiki/Barbary_slave_trade

[stonogo]

Being precise about these things gets difficult; arguably some Arab states are still practicing slavery, but with a veneer of indentured servitude. However, I'd like to point out that the Barbary pirates were not Arabs, and the Trans-Saharan slave trade article you reference covers a similarly vast time scale; if we look at the era during which transatlantic slavery markets operated the scale was at least one, possibly two orders of magnitude larger than Arabian imports of slave labor.

Nevertheless, "slow indeed" is correct, and the Zanj rebellion didn't have much of an effect on North African slave trading.

However, the original question was why Arabian slavery was not as economically potent for Arabs as transatlantic slavery was for European colonies. The answer I'm trying to give is twofold: 1: it was, just vastly earlier than European colonialism, and 2: by the time the transatlantic slave market was established, the Zanj rebellion and other events had had a deleterious effect on slaveowning culture in Arabia. The question as phrased assumes everyone was getting rich from slavery at the same time, which is not the case.