"Best Job the Girl Ever Had"

Now this:

If a single career woman is not  making her age times $1,000 in annual salary by age 30, she should either change careers or marry a career man making $80,000 or better and become a wife and mother. And then live comfortably and afford one additional child for each $20,000 per year he makes over $80,000.

--Attributed to one "Barbara Greenlee, B.S., R.N., ship's nurse, Kauai, Hawaii."  Reprinted in Tom Parker, Rules of Thumb 2, 1 (1987).  The reader is invited to consider how, if at all, the paragraph might be amended to account for current conditions.  For extra credit, estimate how long before 1987 the advice would have made sense.  For the grand prize, explain why the author didn't just say "$30,000" instead of "age times $1,000 in annual salary by age 30."