Why was large-scale slave rebellion almost always
unsuccessful?

Slave rebellions were a continuous source of fear in the American South, especially since black slaves accounted for more than one-third of the region’s population in the 18th century. Laws dictating when, where and how slaves could congregate were enacted to prevent insurrection and quell white paranoia. It’s estimated there were at least 250 slave rebellions in America before slavery was abolished in 1865.

Explanation:

discovery of cape town-portuguese empire

development of africans language-dutch east india company

introduction of railway-british empire