When drug patents expire the drug companies employ 3 strategies against price drop (-): (*) multiply profit by Branding, (+) add value by "Product Hopping" - releasing a similar product, (/) divide profits by "Pay to Delay" - paying competitors NOT to release a generic drug.
Those options are show in this illustration where pills have become calculator buttons.
Article by Richard Davies.
The Economist Newspaper, London
economicsbusinesssciencetechnology