It’s interesting that you put the blame on the FDA. I’m not in the USA, but the effectiveness of a body like the FDA, the FCC, the EPA, FAA and all the others is directly related to how much money they have available and who is running the department; these are determined by politicians.
In other words, medical oversight depends entirely on whom you vote for and why voting is important. It’s the “little” things like this, not the defence or education budgets capturing the headlines that make the difference.
As it happens, every person is an influencer, regardless of followers (…) or content.
The people who are influenced, or said differently, the sphere of influence is dependant on random factors like content going viral when it unexpectedly gets liked and reposted by others.
If you’re asking what size of influence generates income, the answer depends on who is paying.