Why would pharma companies spend money on giving a doctor's office free food every week if it didn't have a return on investment?
Do you think pharma just spends money on this out of generosity? A charity program for office and social workers?
I bet you think advertisements don't work, either.
As a former drug rep, allow me to enlighten you. We catered lunch because it was the only way we could get in front of the MD's, NP's, PA's, and RN's for more than 20 seconds. Doctors don't have time to sit in their office with you anymore because they have to turn-and-burn patients from opening to closing due to ever-falling reimbursement rates.
We were limited to $10/person for breakfasts, $25 for lunch, and $50 for dinners. Breakfast and lunch had to be on-site, i.e. at the office. Dinners had to be speaking events for educational purposes and Docs were not allowed to bring the wife unless she worked in the office in a healthcare capacity(RN, LPN, etc.).
If the OP thinks MD's will write Rx's just to get an occasional speaking engagement(comp for these is only $12-1500), he is sorely ignorant. The companies that are members of PHARMA, which is all of the big/medium-sized companies, can't even give out pens/pads/office items anymore. No gift can be given that isn't specifically educational in nature(think wall posters of anatomy and anatomical models) and valued at less than $100.