Look the bonus or lack thereof is merely the catalyst to leave. The real reasons are because you cant stand the job, the environment, your boss, you feel unappreciated, there's a more attractive firm etc. It is all highly subjective and the grass is always greener at the other boiler room and all that jazz

Anyway the industry isnt a cartel. So it may be possible to find a better firm in terms of remuneration balanced against the job scope