These are the innocent examples, free samples and such aren't the issue. Its with pharmaceutical reps taking doctors out for dinner to promote a drug that introduces real bias, or giving them merchandise (mugs, water bottles).
If the studies are sound for a companies drug then I may be more inclined to read the literature on that drug.
If there is insufficient data to support the drug then yeah you shouldn't bother with it. I can't speak to what all companies do, but where I am at now (and we are small) we really strive to understand as much about how a compound works before even thinking of moving forward into a clinical trial. So when something does get submitted for approval, there is a strong set of publications which go along with it.