However, the grad degree is by no means free. There are opportunity costs involved. $28k per year is on the high end, it could be as low as $10K at some state universities. Instead of languishing in the university for 2 years earning janitor wages for no increase in earnings. Most job positions call for a BS chemist with 2 years experience or an MS for the same pay, get a BS in accounting and start at $40k or go to professional school and make 6 figures even after student loan repayments.
The Ph. D. is no bargain either. There is a huge glut of science Ph. D.'s so most get $35k post-docs for more years of languishing in the university. So you've spent the better part of a decade at the Univ living like a pauper and have poor job prospects to show for it. At this point the median income seems unreachable. It is just astounding to me that anyone would go into science anymore.
This is just not all true.
Yes, 28K is on the high end. But you can not just look at actual hard numbers, they are irrelevant. You have to look at the cost of living of the location.
A lot of jobs do call for BS Chemist, yes, because there is A LOT of work out there that does not need highly qualified people. That is how the world works. We need janitors, they are an important part of society.
But to say a BS or MS in chemistry pays the same, is completely ignorant.
As far as what you said about post-docs, well the average "chemistry" post-doc in the US is $47K a year. Much higher then what you claim, or what you claim for the 40K starting accountant, etc.
If you look at post-doc biochemistry, the average is $63K a year.
Materials science, post-docs, which many chemists are qualified for, average at $66K a year, post-doc.
Polymer Chemist average at $44K a year, post-doc
Analytical Chemist average at $55K a year, post-doc.
Organic Chemist average at $52K a year, post-doc.