Not true at all. Most labourers have nowhere close the pricing power necessary for this to be true. Information is obfuscated (legally of course) on purpose.
Let's take a Principal Engineer. A bad choice to make my case with, because among others, they do pay rather well. For a Principal Engineer, it is sort of a job requirement at that level to save or generate of the order of ~100 million dollars per year. An outsourced engineer sees nowhere near 1/10th that amount in his/her salary.
If you believe you are seriously underpaid, explain to your employer what value you are creating, and negotiate.
If you start your own business, you'll find out exactly what you're worth.