The data at those links indicate the demand for child care workers is more than 40x the demand for physicists and astronomers combined. Yet, childcare workers make only slightly more than 1/5th the wage.
This is because skilled labor is not fungible and different jobs are on different demand curves.
Maybe I misunderstand your argument. I thought your main point was that pay may be high despite demand being low, and vice versa. I'm sure there are exceptional cases where this is true, but the examples you provided illustrate something very much counter to your point.
In your examples, pay and demand are low for all three professions, chemists, child care workers, and astronomers, according to the BoL.
My point is that each profession has its own independent supply and demand equilibrium, and not every market even operates at equilibrium. The relative wages of two entirely independent markets for labor don't indicate relative demand.
Okay. I didn't make that comparison. I see why you might though. For clarity, my point isn't that they make less than any comparable. It's that taking into consideration the cost of acquiring the degree, it's unusual that the pay would be about median in keeping with uneducated laborers. An explanation like unusually low demand (or market saturation) is likely to be the cause of that pay deficit. In this case, it appears to be in fact.
