Why was the extreme form of social inequality (slavery) inherent in all ancient states?

Why was the extreme form of social inequality (slavery) inherent in all ancient states? what was the situation of slaves in ancient egypt? indicate the sources of slavery.

Of course, it was slavery. The slaves here were the most oppressed and disenfranchised. Slaves were sent to the hardest and most difficult jobs. In this connection, they were quickly depleted and soon passed away. In those days, it was possible to become slaves due to non-payment of debts, and also those who fell into war captivity became slaves. For example, an army of conquerors came and conquered a certain territory. The inhabitants of this territory were essentially turned into slaves.