> But that doesn’t mean there aren’t a hundred possible pros and cons for one type of molecule versus another to treat XYZ condition in ABC population, with potentially huge variation between patients both explained and unexplained.

There really aren't when comparing different molecules with the same mechanism of action. Individual hospitals and health systems will usually tender out their contracts to the cheapest molecule in each class, or sign up with a buying group that does.

It simplifies prescribing, inventory, distribution and administration too.