It's an interesting concept to suggest an effective put option for the government, based perhaps on the auditable costs of successful R&D. But this would probably have to work both ways - also including a put option in favor of pharma for R&D that was unsuccessful. R&D spending would become more transparent as a result (inflated, perhaps, to try to hedge against the government intervening on a hugely profitable opportunity), but in any event still entirely recoupable. Different sort of risk/reward algorithm at play, but feasible.