[SomeoneFromCA]

It is far easier to switch an employee than employer, as decision is made assymetrically - the decision maker, the manager of your manager, for example, has zero emotional investment in you, compared to you and your being accustomed to your place, social relationships etc.

EDIT: It is also true that too frequent switching jobs will have negative consequences for your employability; and high attrition, even if it becomes a public fact, would have little consequences for desirability of the job.