I also think people way overestimate how much the average physician knows about new drugs. They don't have time to do it. Talking with a sales rep for 10 mins to get your questions answered can be very efficient.
A few years back a friend told me about his company (pharma) that was selling a drug for hepatitis C. The drug was going to be obsolete when a competitor launched, so they wanted to make sure docs didn't buy a ton of it otherwise they'd be returning it.
What was amazing were the number of doctors who continued to buy it. The sales reps had to go to the office and ask "why are you buying this drug? the new drugs are so much better, it would be unethical to continue to use this drug".
The doctors had no idea the new drug had launched.