Certainly most women couldn’t make six figures if they opted to enter the workforce.

That said, the six figure number is probably a bit dubious. I assume the estimate was based upon the mean value of the cost to hire a professional cook, laundry machine operator, janitor, psychologist, etc.

There is no plausible reason to think that any non-professional person could approach the average level of productivity within a given industry.

The large majority of stay-at-home parents simply provide low quality services because they are not able to specialize. Thus it is highly unlikely, that the value of these services amount to six figures.

In addition, the qualifications needed to be a good SAHM are (in my opinion) good common sense and some life skills that most people already need in order to take care of themselves, let alone others. These are skills that almost all people have. And we know from looking at the job market that when jobs do not have very specialised skill requirements, they tend to have low salaries.

I think a more interesting estimate (that was discussed in the Feministing comments) would be to take the 40 hours worked per week plus ~60 hours of overtime and multiply that by some minimum wage, say $7 per hour. That comes out that a SAHM’s work is worth about $50,000, at an absolute minimum.

Obviously the true value is somewhere between these two figures. However, I suspect it’s a bit closer to $50,000 than it is to $120,000, and I think it does a disservice to the argument that women’s work is not valued to use estimates that are not realistic.