The marketing team for a protein shake is not making billions. If you mean the CEO and shareholders then you can’t compare them to scientists chasing grants, that’s not an apples to apples comparison.
All the researchers I know are driving old used cars and scraping by. Nobody is rich.
All the big firm researchers/marketers I know are living very comfortable upper class lives, and don't want to jeopardize that with any 'counter findings'.
How hard is this to understand:
“It is difficult to get a man to understand something, when his salary depends on his not understanding it.”
― Upton Sinclair, I, Candidate for Governor
The person chasing grant money is getting a few thousands of dollars.
The person chasing a food product is getting billons.
The incentives are very different in scale.