Why do some partners at MBB leave? Isn't the money at equity partner level pretty good?
A lot of reasons:
1) You get asked to leave. At McKinsey you have 6-7 years to make Director from Partner, and if you don't make it you will be asked to leave. A pretty small percentage make it
2) A perfect opportunity comes along. As a partner you get plenty of very interesting job offers. Occasionally one is just too good to turn down
3) You want a change of lifestyle. Even as a partner you will be working long hours, and spending a lot of time on the road. Some people just get tired of this after ten years or so
A combination of 2) and 3) is probably the most common