I do not think that the use of Infusion centers is nefarious but a practical move. When having cataract surgery, I learned that the hospital/surgical center was the one ordering the lens and responsible for having the correct one at the time of the surgery. Medications like Prolia are not cheap; far more costly than flu/pneumonia/etc. vaccines that doctors may keep on hand in their offices. Instead of each endo/rheumatologist keeping them in stock or ordering for an individual, it is far more convenient for an infusion center to do the ordering for multiple doctors. They may be able to keep a small inventory in stock dispensing on the first in/first out basis. They might even be able to get discounts based on larger orders.