Maybe we just took all the low hanging fruit? - Manufacturing can't get that much more efficient without a lot of automation, which is a very hard problem that

Maybe we just took all the low hanging fruit? - Manufacturing can't get that much more efficient without a lot of automation, which is a very hard problem that requires expertise in computer vision, robotics, mechanical engineering, and domain knowledge. That's expensive and hard to organize. - Per capita energy consumption in the developed world is already high and will be hard to increase while also decreasing CO2 emissions. Especially given entrenched interests and the inability of most governments to complete large projects on schedule. - There's only so many ways to move and rearrange matter in ways that are fundamentally revolutionary. We found a lot of them in the 1800s and 1900s. Jet engines, motors of various types, lot of chemistry, power generation stuff. There are still interesting developments going on (especially in biology), but mostly they are incremental advances, not something that unlocks entirely new capabilities.