if electricity is limited, which in reality it is, then yes I agree with what you said.. otherwise, I see no problem with my point.
The way I think about it as an economic optimization problem. You have an input and output, as well as a belief of what the bitcoin value should be, all you have to do is solve the optimization problem and see what hash per dollar *given* your electricity constraint and bitcoin value belief yields the maximum.
The average person may not get this, but it is not hard to educate.
You clearly have the best answer and it was not an intuitive one either. "If electricity is free .." Then you only optimize for hashes per $ and do not factor electricity. It is pretty obvious once pointed out.