This is somewhat disengeneous.
It's only measuring carbon. Of course a factory will be more efficient per unit of output.
The total environmental footprint is more important as is which markets that output serves.
Here in NZ, with a population of 5m we export enough dairy and meat to feed 40m. So we could avoid all the local environmental impacts and those of transporting that output to the world and still feed the entire population with only ~10% of the industry output.