Upon receiving any sort of medical injection, you’re also typically recommended to follow up with your doctor.
Yes, if you have existing medical conditions that your doctor is aware of, they may be in a better position to point out any potential interactions between those conditions, any treatment you already receive, and a booster. But I'm guessing that this isn't a description of most of the population.
I'm also not sure that most doctor's offices really want every single patient calling in to ask "Should I get the booster?", and might simply be unable to deal with such a flood of questions.
There's also the little detail of millions of Americans not actually having "a doctor" in the traditional sense.
https://www.gezondheidsplein.nl/nieuws/wisselen-van-huisarts...
….seriously?
Your doctor
Good lord we are in for some bad times