Earlier quoted context omitted.
You (and the article) are ignoring smaller companies. In those, you often have the salary negotiations with the owner, or a partner. Your salary comes (effectively) out of their own pocket, and recruiting you is quite possibly a significant and risky investment for the entire company. In these sorts of situations, negotiation is much harder on a personal level, since the company is not a faceless entity. The company…
Small companies with smart hiring managers or owners should know that if they pay candidates, especially highly skilled ones, not enough, they will probably jump ship after one or two years which is exactly the period after which employees reach a level of productivity that brings enough value for companies to justify the hiring.
Either my experience is exceptional, or your implication that money is the only thing that matters about a job is wrong.