Imagine if there were a hierarchy of professional theaters. I mean, there is one already, sort of, with LORT theaters, but they still exist independently of one another. I'm talking about theatrical affiliations, a la pro sports, where you've got your (for lack of a better term) "Major League" theaters--your Steppenwolfs, your Alleys, your CTCs or Dallas Childrens--and below them, you have a second tier where these major theaters develop talent they hope can one day move up to "the show," and then below that there's another tier (I'd imagine the Players probably fit in here somewhere), and somewhere in the midst of all that there are professional summer stocks, where theaters occasionally send one or two people per year a la NFL Europe. Or something. Then you've got all the other theater companies that exist but don't feed into the mainstream theaters, like we have now, only the people working there are mostly hoping to get lucky and get a big break with one of the affiliates to work their way up.
Every year, the major theaters get together and have an eight-round draft. All the theater undergraduates from across the country (as well as equivalent development/educational programs around the world) are eligible. Undrafted thespians can still catch on with a minor-league theater and hope to catch the parent company's attention. Theaters can trade anybody; you're looking for an ingenue but think your ATD might be ready to make the step up to a full time TD? Great, we need a TD and have a glut of thirty-year-old women who look like they're sixteen! We'll trade you one or two plus a mid-round pick for your ATD. Fax the deal to American Theatre Wing. The theater that finishes last in the box office the previous season picks first in the draft. Draft picks can either go to work professionally with an entry-level contract of limited term, or the parent company can retain their rights while they go on to pursue a master's degree. After a certain number of years and the contract expires, though, the actor/designer/director/whatever becomes a free agent and can sign with any theater in the country.
Feel free to thrown in your own addendum to the theater-sport world in the comments, cuz this is kinda fun.