The freedom to just up and move jobs isn't equally available for everyone.

Anyone who doesn't have a permanent right to work (eg on some kind of visa) can find it hard to switch jobs.

If you live in a place where Healthcare is tied to your employer, then that can cause problems, too, if you/a family member have some kind of chronic/ongoing medical issues.

If your salary package has some kind of deferred portion, then that can also make switching difficult.