And the socialist's view is that exchange is more often than not unfair for the worker, and the rewards are paltry compared to the amount of work being done. Especially nowadays when you have people working longer hours without their wages getting any better.
Then you find a fairer employer, or you accept that the work you are qualified to do will be worth less. Of course that's not always the case and I'm not saying workers don't get underpaid, but I'm speaking only on principle