That derives from the system they’re operating in though. In a capitalist society the notion that unless compelled by government intervention people and corporations will act in their own self interest is exactly what I’d expect.
If a company is filling a role and 2 similar applicants get matching offers and one accepts the first and the other negotiates I wouldn’t expect the company to go back to the first person and offer him more to bring them to parity.
If a company is filling a role and 2 similar applicants get matching offers and one accepts the first and the other negotiates I wouldn’t expect the company to go back to the first person and offer him more to bring them to parity.