[penguinduck]

The more a person wants to do a job, the less compensation they will demand because the emotional satisfaction they get substitutes for a part (or sometimes all) of the compensation. When there are a lot of people who have a strong preference for doing a job in a particular industry, they collectively drive down the price of their own labor into the ground.

Companies will only pay what they have to.

Some examples of industries where tons of people work for shit money (less than a person of their abilities could earn in other industries) or even sometimes for free because of an emotional attachment to that industry are showbusiness, art and academia.

Then you have the opposite examples, like working on an oil platform - most of those people would earn less money if they had picked a different industry, because they have to be paid more to agree to live on an oil platform and do a shitty and dangerous job.