It's a typical engineering fallacy that if you build it they will come.
The public, including doctors, have so much information to consume that if they aren't re-educated on treatment choices the drug will die and so too may the company.
Advertising is absolutely critical in recouping R&D costs. And that's assuming the drug makes it to market (which a majority do not).
>In the United States, it takes an average of 12 years for
>an experimental drug to travel from the laboratory to your
>medicine cabinet. That is, if it makes it. Only 5 in 5,000
>drugs that enter preclinical testing progress to human
>testing. One of these 5 drugs that are tested in people is
>approved.