Earlier quoted context omitted.
This may come as a shock to you, but marketing pharmaceuticals is really no different than marketing other products. It really comes down to educating consumers about your product. Doctors as decision makers are not some monolithic block of individuals who are super educated about every product on the market and every piece of data. Just developing awareness of new drugs is a huge job. I'd say less than 5% of doctors…
Except it's not marketing products to doctors, who are the gatekeepers to access. It's marketing to consumers, who aren't informed, and are then used to badger doctors to make them prescribe medicines they heard about on TV.
Some resources:
[1] https://www.sciencedaily.com/releases/2018/05/180514132441.h...
[2] https://www.pewtrusts.org/en/research-and-analysis/fact-shee...
Plus, this classic Scrubs clip describing a particularly chauvinistic (but truth-in-television) take on the practice: https://www.youtube.com/watch?v=VMXa0U4WZyU