It isn't.
In the past year or so, I've had many chances to reexamine what could have been called (anachronistically) the "Woke" philosophy that I developed as a teenager in the 1990s. Because when I had my first exposure to thinking about the world critically, and to understand intersectionality and how institutions controlled and defined our life, it seemed an important breakthrough to realize that if you have to work to live, if some people in the system have the power to make decisions, and the rest of us are stuck needing to adhere to the system, wasn't that effectively slavery? Why should we proclaim ourselves "free" when we were caught in a web of debt and necessity that kept us tied to a limited number of people that could give us the things necessary for life? Wasn't this just slavery in another name? Wasn't the common belief that we had control over our lives, that we could always "pull ourselves up by our bootstraps", just a result of propaganda, and that we were all victims of Stockholm Syndrome?
The short answer to these arguments, and all the many good arguments in the same matter, was that it was a good thing to think about, a good thing to understand, but that slavery, as an institution, especially as it was practiced in the United States, was so cruel, so barbaric, and so dehumanizing, that slavery, and wage based economies, should not be compared. Slavery and wage systems are both based on power imbalance, and both are supported by a series of institutions. But "wage slavery" is not dependent on cruelty and dehumanization. My own understanding of slavery, as practiced in the United States, is that the economic justification for it was secondary, that establishing a cruel system where some people were dehumanized so some people could feel better was actually the primary purpose.
So even though I think it is good to be aware of the spectrum of ways that societies control people, I also think it is important to remember that there are sharp discontinuities in that spectrum. Because something shares features with slavery does not mean it is slavery. "Wage slavery" is not slavery.