Agreed, employers often take advantage of market illegibility as it allows them to underpay people who don't know what their market value is. The employment market has very imperfect information, and the information asymmetry is usually in the employer's favor.

In order to get the best of both worlds (reasonable hours and high pay) as an employee, you not only need to be a top-notch employee, but you also need to find a top-notch company to work for. Middling employers will either underpay you or overwork you, and the worst employers will do both.