I think this behaviour can also be inline with the other side of the problem though:
Employees perception of growth: it's easy to feel like you are learning more when it's something brand new because of how easy any topic is at the beginning, and you inevitably get more new things when moving; whereas pushing your existing abilities and strengths into incrementally more advanced areas is harder won and requires more fortitude. Also focus on short term financial gains over long term career growth: Although jumping ship has a tendency to force a re-align of financial reward with ability, it also resets your progress reducing your experience on long term project and denying yourself to opportunity to learn from the long term consequences of your decisions, which in turn can affect your long term prospects and financial rewards. (I am suspicious of candidates with a employment history of a series of short stints for this reason, because they did not have to live with the results of their output).
It's subjective, sometimes it's truly not worth staying, sometimes it is... but I suspect many people confuse short term gains with reasons to move, when their current job may in-fact be of more mutual benefit long term.
Employees perception of growth: it's easy to feel like you are learning more when it's something brand new because of how easy any topic is at the beginning, and you inevitably get more new things when moving; whereas pushing your existing abilities and strengths into incrementally more advanced areas is harder won and requires more fortitude. Also focus on short term financial gains over long term career growth: Although jumping ship has a tendency to force a re-align of financial reward with ability, it also resets your progress reducing your experience on long term project and denying yourself to opportunity to learn from the long term consequences of your decisions, which in turn can affect your long term prospects and financial rewards. (I am suspicious of candidates with a employment history of a series of short stints for this reason, because they did not have to live with the results of their output).
It's subjective, sometimes it's truly not worth staying, sometimes it is... but I suspect many people confuse short term gains with reasons to move, when their current job may in-fact be of more mutual benefit long term.