Being a great director has little to do with being a great artistic director.
Directors direct projects. Artistic directors use a collection of projects to fulfill a mission that serves a community. These are completely separate skills.
ADs who direct some projects for their own company risk treating those projects as precious. Too often, they break rules for their project (organizational mission, budget, marketing, etc.) that they would never allow an “outside” director to break.
And in too many cases, when the identity of a nonprofit arts organization is too closely entangled with the vision of an artistic director, the organization’s brand is that much more difficult to recuperate when inevitable leadership change occurs.
After all, succession is not merely an artistic director handpicking a successor, is it? A company is greater than any individual leader, right?
Why is it assumed that it is an absolute good that an organization outlive it’s founding artist/leader? Sometimes it is not. The organization supports the work of that artist or a particular artistic collective and then rather than prop up same faint echo or hollow shell, it simply ends. Meanwhile other organizations arise with other founders. It seems to me that this is a choice that is made sometime in the life of a company. For example I worked with a puppetry company in which the Board and administration was pushing to expand and create a new young company to continue the work of the founders. At some point, the founders said “No” and so everyone was clear that the company and the works would retire with them.