Only small proportion of patent portfolio applied for before product launch, patents continue steadily after launch, often exponentially, until total patent expiry. I see this, among other uses, being used against the ‘but those 20 years start shrinking once you look at all the years it takes until product launch’ argument.
“Figure 56 depicts a clear trend in the case of the top ten INNs for companies to file significant numbers of patent applications well after the first product launch, in particular immediately before or after the primary patent in the portfolio expires.”
pages 173-179 [really worth reading those 6 pages]
Pharmaceutical Sector Inquiry – Final Report, European Commission 2008