This allows others the opportunity to push the limits of their own potential and encourages them to explore their creativity, thereby freeing principals to apply their own energies to their pivotal functions. This is sometimes a natural evolution. Other times it is by economics driven design, reached through the determination that at that ratio, there are adequate revenue generators to provide the profit that, in simplistic terms, converts to compensation that owners target for themselves. Prehistoric hunters learned this, as evidenced from the traces of their activities, and human nature and capability has not changed a whole lot since. As with most attempts to quantify professional practice, particularly organizations in the more creative reaches, the concept of the sanity factor has its flaws and inconsistencies.
Some people respond very effectively to the challenge of increasing pressures.
The culture of some firms fosters a truly collective and collaborative approach. Some firms' client and project mix results in significant changes to the point at which declining sanity begins, and some principals' personal styles accommodate larger numbers of staff.