The first name on the study was a Wash U professor for over 25 years. The 2nd name has so far spent a significant amount of her life in academia. Only the 3rd author appears to have spent most of his career in public service.
Nonetheless now they all work for the Fed, so these particular ex-professors lacked the supposed conflict of interest you imagined at the time of publication. Not that I think it matters at all. There are papers on the causality of education from career academics claiming anywhere from little to none, and I haven’t seen any papers claiming it’s very very high, so the broad outcome is exactly the opposite of what would happen in your imagined scenario if it were true and researchers were being defensive and biased about the value of education.
Your comment above is FUD, not based on knowledge of the research or the researchers, but pure speculation, which is why it’s not fair to say.