Life just sucked for everyone back then. Being a slave isn’t even the worst fate you can suffer from. It wasn’t uncommon for people to go into more indentured servitude style of slavery to pay off debt or just to have a roof over their head. Slave owners have a interest in keeping their property and investments alive and well. If you had some valuable skills, you could live pretty well at the time like being able to teach the children of elites.
With that in mind, you can kind of see why it wasn’t on the top of the list of things to do on earth.
Not that I condone any form of slavery. But our modern context of slavery is usually from the trans Atlantic slave trade. Slaves during the Roman times were somewhat different in their roles in society. Most can even earn their freedom.