Interesting perspective. Mines a bit different..
I agree specialization has allowed the expansion to other fields. Fields like microcontrollers, biological development, energy research, etc.
This is why we see an exponential growth in development of new products and new science. If those same people were required to work in the fields to eat, we wouldn’t see the expansion.
... now ... how does this work In practice? How do we get these efficiency gains in agriculture and other necessary parts of life?
Cheap and transportable energy. Fuel, gas, etc. if we want to reduce the work week we need exponentially cheaper energy OR research into new forms of energy production. The later is currently happening and needs to continue to happen. In the mean time, we also need cheap and transportable energy.
For reference, I own a farm. I code professionally and as a hobby raise cattle and food. I can do that only because I have the fuel to run a tractor and the wireless internet provided from the satellites. To your point, in a 50-60 hour work week I can produce enough food for 20-30 families for the year AND be a highly skilled tech worker AND raise a family. All because of fuel.
Now to my point, in my opinion, specialization has less to do with it. Cheap energy is what allows it. Anyone could raise cattle or grow food with minimal training. But without fuel you can’t produce food for more than a few families per year.