Combining multiple medications( of the same class) can sometimes work, and for tough complicated patients may be the way to go , the major problem with poly pharmacy is that most people get a big 15 minutes to see there doc for a med check , so it contributes to doctors getting lazy , they throw a bunch of med's at you and hope something works , the downside to that is generally it's a mystery as to which drug caused the improvement , thus you then are stuck taking a bunch of drugs that are doing nothing, but if you do a drug taper you risk causing the patient to decompensate if you happen to taper the one that works the patient can end up inpatient wondrting what happened to there life ?, so many doctors are becoming gun shy of doing that , because it screws up the patients potential recovery and is a risky time consuming strategy that many doctors don't want to do the work and have the appointment time to really over see treatment, in this day and age doctors aren't practicing medicine ( and you rarely meet one who is good at it ) they are practicing what there employer and the insurance industry will accept , and devoting time to one patient is highly frowned on because every minute they spend giving one patient the quality care they deserve means that the patient turnover rate gets messed with .
A comparison would be a restaurant that puts uncomfortable seating in , it encourages people to eat and leave rather than staying around and taking up space at tables that aren't making them money , if that put nice seating and chairs in , the table Wont turn over as fast, then they have to charge more for every menu item to make up for the lost volume.