[pluma]

> Slaves under ancient Rome could earned wages and sometimes bought themselves out of slavery.

Not just that, in some cases slaves could actually be better off than some free citizens at the time. Although I doubt this kind of vertical mobility was particularly common.

And of course, absolutely speaking, a first world citizen today living in poverty is still far better off than a rich nobleman a few hundred years ago. It's the unequal distribution we find unfair, not merely the individual situation.