Starting a successful company, in any field, is usually a big accomplishment. Starting a successful theater company is very nearly impossible.
My friend did it, ran it for 10 years, then had to quit before it swallowed her up completely. Now, as far as what to do next... she's kind of at a loss.
One frustration with this field is the lack of a clear 'next step.' There's no career ladder. Accomplishments don't build on themselves; they're just moments of satisfaction, usually followed by wondering if anyone will ever want to work with you again.