That feels like it'd be a small minority of cases, because the person who determines how much value an employee provides usually is incentivized to minimize how much to pay that employee.

If you pay too little to an employee he will just go somewhere else. The magic of the market! That is why I am all for free market (real, free market) with minimum regulations. Because employers end up fighting for the workforce and it benefits the workers.

This depends on more variables, but the goal is to avoid barriers and regulations so that the wealth increases, since these break monopolies or de-facto monopolies (via absurd regulations).

The market is no magic, it commoditizes most employees.

depends on the skill required for the job. It is a natural consequence of how things work. If you do not like it, you can always try to be the one who hires and fires.

But yes, that has its own set of risks. Risks that are disregarded all the time making employers the bad part of the story and employees the good ones. This is not at all like that you can find good and bad on both sides...

An employer is not bad for trying to pay you less. The reverse argument should be true also: the employee is bad because they want more (than they deserve or produce).

No part is bad, it is natural to want to maximize our outcome. It is how things are. I see many people having a problem with this thing. But they only have the problem when it is the other who tries to do that. When they do it for their own benefit then everything is fair and alright.