The other aspect not discussed here is that even if actors decide to stop auditioning and take full-time positions in theatre related fields, those salaries are incredibly low, too—with most salaries in the $20K to $40K range for positions like stage managers, theatre tech, company managers, casting, talent management and marketing positions. And that’s in NYC and not just entry level jobs . Recenly, there was a spread sheet going around Facebook in an attempt to disclose how poorly these positions pay in an effort to rally the troops to demand more money.
Other college grads with non-arts majors enter fields just out of school and get entry level jobs in the $50k to $60k range. Few people in theatre ever achieve those numbers many years post-graduation if they stay within the theatre industry exclusively.