The issue (for the masters, and besides any ethical issues) is being a slave master is a very tenuous position, and prone to revolts.
Too capable (but also valuable!) slaves tend to be self sufficient and strong enough to throw you off.
Too weak (and therefore non-valuable!) slaves tend to be easy to control - but are a huge drain on the system, including ‘master’ management, which is often the most constrained resource anyway in any hierarchical system.
Too capable (but also valuable!) slaves tend to be self sufficient and strong enough to throw you off.
Too weak (and therefore non-valuable!) slaves tend to be easy to control - but are a huge drain on the system, including ‘master’ management, which is often the most constrained resource anyway in any hierarchical system.