So, your statement is true because you say that it's common knowledge that it's true?
> Primary and secondary production, is a big fat chapter in any Ecology handbook
OK, then kindly provide one of these ecology handbooks that proves your point
> If nobody is trying to produce a natural sized cow sculpture made of vanille beans, there must be a reason
What do you even mean by this?
Not, my statement is true BECAUSE is has been proven extensively and is common knowledge that it's true. There is a difference. There are extensive databases, plots and tables about how many food you can expect to produce from each organism by unit of time and area. Is the basis of a main branch of ecology: Trophic chains and energy.
To say than growing Soy is more efficient than to breed Polar bears is a repeated lie, trying to make simple things that aren't simple. Not. It depends on the ecosystem, context, temperature range, soil, and climate. And is the same with breeding cattle.