> Energy is the fuel for machines. And machines build more and faster than humans
Sure.
> To increase productivity, we need more machines,
That is just one way to increase productivity. You can also make more efficient machines, come up with more efficient production processes, find alternatives to existing products that are more useful for a given task per quantity, and similar kinds of concepts. This is the point GP was making (there are more ways production changes than increasing energy used), not that energy is completely unrelated to production as a whole.
At any given efficiency, more energy means more productivity (in the same way: at any given amount of energy production, more efficiency means more productivity). Yes, we should be increasing efficiency where reasonable, but we should also be increasing energy production.
There is a reason that the Kardashev scale is about energy utilization.
Correct, we can innovate and make the "transformer" (i.e. machines) more efficient (i.e. use less energy for same output). But the thing is, if energy was cheaper and more available we would just produce more.
The reason why now we most enjoy some time off (weekend, vacation, retirement) is thank to the machines that can produce more with less humans. Now humans mostly drive the machines.
I guess the ultimate extreme evolution would be machine driving machines, so humans could be out of the loop, except for the initial input goal. And machine would extract/mine/recycle, transform, transport, deliver everything we ever need. It would be one big machine (with lots of energy) extracting (and hopefully recycling) earth elements to satisfy humans.
Sure.
> To increase productivity, we need more machines,
That is just one way to increase productivity. You can also make more efficient machines, come up with more efficient production processes, find alternatives to existing products that are more useful for a given task per quantity, and similar kinds of concepts. This is the point GP was making (there are more ways production changes than increasing energy used), not that energy is completely unrelated to production as a whole.