Low-hanging fruit depletion is a problem, but there are ways of dealing with it: - A larger number of people searching for the next Newtonian apple all over th

Low-hanging fruit depletion is a problem, but there are ways of dealing with it: - A larger number of people searching for the next Newtonian apple all over the place. - A smaller number of larger groups that pursue a narrow area with intense focus. That’s more like “work” though. - New areas. Especially software. Google, Facebook, Microsoft, Apple were created by tinkerers with the privilege of free time. This process did not yet stop. To your other point, not every idle person will pursue new knowledge. And that's ok. A larger number of idle people will contain a larger number of tinkerers.