Companies are well accustomed to bullshitting employees, so many people do fall for their lies.

Or they may have not been lying but just reacting to circumstances. They can’t give everyone everything needed to make everyone stay if the threaten to leave but they can do it for the one who does actually threaten to leave.

As a team lead I don’t believe in convincing someone to stay if they took an offer. Their heart and soul has left the building!