I think that's an excellent question to pose, as well as a realistic one. Statistics say that most stage managers rarely stay stage managers the length of their careers - especially women or those with families - though many transition into artistic administrative or other arts-related positions. You have to keep in the back of your mind the fact that your career as a stage manager means you will gain experience that translates well into several fields, should you desire to leave the arts altogether, and it's always a good idea to keep an eye out for those fields that interest you.
I know realistically that I won't be doing this forever, because at some point I expect the whole process of managing a production will lose its appeal and I'll wish to move on. If you mean 'what would I do,' as in what would be my next career step, I imagine I would be one of those that would transition into arts administration, most likely company management or administration within an arts department of a university/conservatory. I interviewed for positions in both within the past year, company management in Arizona (to be closer to family) and within a university (arts admin at Yale - on two separate occasions), because it would have been beneficial to my family (I currently bring in the only income). Genuine relief came over me when I didn't land any of the positions - which tells me I'm not quite ready to let stage management go.
(And I won't quote What I Did For Love, though I might start humming Finishing The Hat...)
