The simple answer is $$ kick backs for the meds. I asked my cardiologist why he prescribed a whole list of meds for conditions I didn't have.  He said that is standard procedure for anyone who has had heart problems. When I started listing the common side effects and drug interactions and asking for specific reasons. He said you really don't need them. I am on zero "heart" meds, only taking 1/2 rate of a blood thinner, because of genetically thick blood. 

Much of what is prescribed is unnecessary, and what I'd call Shotgun medicine.  Also eye opening how they do the same thing with old people. My father-in-law was on 52 medications, many were for opposite things i.e. 2 High blood pressure and 3 low blood pressure medications at the same time.  Also anti-seizure meds, when he's never had one , nor symptoms of one.  Just another one of those, well if you have "this" illness, you must have "this" as well.

I trust the medical establishment less, the more I'm exposed to it.