>maybe it should be based on revenue generated The pitfall there is that there is no guarantee of revenue. You also invite the possibility of predatorily delay

>maybe it should be based on revenue generated The pitfall there is that there is no guarantee of revenue. You also invite the possibility of predatorily delaying revenue generation. Potential revenue generated would be more on the nose. In another sense, sustaining a patent until it generates sufficient revenue can be seen as oxymoronic to the idea that patents incent products that serve the public interest - since, if the patent is not creating value, how can it be in the public interest? Patent lifespans are already sort of considered based on potential revenue generated, and use number of years as a proxy for that