Average Salary: $49,690
Expected Lifetime Earnings: $2,074,000
This is the theatre. You're either making bank on Broadway, or you're the other 99% (and even when you're on Broadway it's still not great). Most theatre companies don't make money off their ticket sales and are dependent on the kindness of strangers.
Even commercial productions are fraught with failure, as only twenty percent of Broadway shows make their money back (source). Producers pass on this problematic financial model to their employees (a.k.a. you), which often means they need to get paid back before you see a cent.
Early in their careers, directors will often work for free (or if they're lucky a small stipend, which usually covers about half a tank of gas) (source).
However, once they start working consistently on a professional level, most will join SDC, the Society of Stage Directors and Choreographers (yes, directors are put in the same category as people who wear tights professionally). This is the Director's Union and will ensure a director is paid appropriately and receives health benefits if working regularly.
At the union level, directors should not be making less than $500 per week, although exceptions can be made if the directors want to invest their time developing a show that will make them money later.
It just goes up from there. For a typical four-week rehearsal process at a recognized regional theatre, a fee of $5,000-$20,000 can be expected (depending on the size of the house).
Remember that this has to cover pre-production, all those hours spent pulling out eyebrow hairs one at a time while considering if Ophelia's dress should be peach or salmon. This fee must also cover all the time spent sitting on a couch that smells like tears, waiting for the phone to ring with another job.
By the time you're directing on Broadway, you should expect to be making ten times this amount, or $50,000 and up per production. This usually happens regardless of a show's success, because by the time the show is opened (and suddenly closed), you've moved on to the next one.
The other route you can take is to become an Artistic Director of a theatre and hire yourself. Then you can direct until you die. Literally. This job involves a lot of administration and fundraising (read: 101 ways to butter people up) that may or may not appeal to you.