At Unicorn we have supported personal growth in the theatre. I say its all a click at some level. Mamet writes his plays with his favorite actors in mind and he uses the same actors over and over again. There is nothing as satisfying or fulfilling to a director as working with an actor you know really well, but parts are earned. Most often casting choices are built on a strong feeling of personal believability and the talent and commitment of each given actor.
Most times there are no free rides.
For generations of actors, it has been a phrase which demands a chivalry, and stoic martyrdom which is worthy of a Saint.