A slave to biology
It strikes me that in a very real sense we are slaves to our biology. What I mean by this is that because our bodies require a constant input of resources for maintenance, we are indebted to that requirement. This puts us in a kind of debt bondage: we have to work to pay off that biological debt, and the penalty for non-payment is death.
For that reason, the notion of wage slavery seems short-sighted to me; it's not wages that are responsible, it's our biological needs that give power to those wages. If some freak of genetics caused you to be biologically self-sufficient - powered by the sun or some such - you would have no particular need to work. The idea of wage slavery under those circumstances would seem very far-fetched.
Indeed, if you earn enough money you can reach a point where you have enough to cover your body's needs for the rest of your life. I would say that at that point you have purchased your biological freedom. Though obviously some people don't earn enough to do that until very late in life, and some people inherit resources enough to be born free.
To accept this view is to accept the notion of biology as unfair. Why should we be born into a world with this debt attached to us? Wouldn't it be more just if we could start with a blank slate? And indeed to some extent many countries accept this in the particular subset of medical needs. We acknowledge the unfairness that some people are born with or acquire expensive medical problems that drastically increase their biological debt, and we pay to free them of that debt.
But you have to ask, isn't anything that causes you to get sick and die a medical problem, even if it affects everyone? And shouldn't it be a priority for us as a species to remove that burden?