Well, there’s literal wage theft, which other folks have explained clearly here, then there’s figurative wage theft, such as artificially depressing wages in order to redirect money to executives that they couldn’t possibly spend nor reasonably need.

This sense of wage theft is more nebulous and therefore easier to be confused about. It wouldn’t surprise me if you asked ten people about got ten different answers about it. There’s nothing about my answer here that’s authoritative; it’s merely a short summary of how I understand the term as commonly used.