Most associates do not make partner because 1) the majority of firms are too small to offer advancement opportunities to their associates, and 2) most managing partners prefer their principals and general partners to have some sort of entrepreneurial experience before being trusted to make investments. As a result, most associates typically work at a venture capital firm for two to three years before being leaving to earn their MBAs, work in operation roles at a portfolio companies, or found a startup.
For associates lucky enough to be on the partner track, the typical advancement path goes from associate, to senior associate, principal, general partner, and then managing partner.