you've given an answer regarding consumers, although it's wrong
What makes you think you can just say "wrong" without any kind of argument to back it up?
If the harvesters are also the suppliers, then we'll just call them harvesters, because it's their harvesting behavior we're interested in.
Let's just call them suppliers instead of reinventing the wheel. The short answer is, marginal revenue approaches marginal cost and the demand at that price point drives the supply. I think it would be easier if you would just make your point instead of playing Socrates.
So, why, in the presence of scarcity, is your explanation of consumer behavior irrelevant?
That's your job. Please explain why it's irrelevant since you claim it's so.
You've got it backwards actually (See:
http://en.wikipedia.org/wiki/Supply_and_demand).
At least two assumptions are necessary for the validity of the standard model: first, that supply and demand are independent; and second, that supply is "constrained by a fixed resource"; If these conditions do not hold, then the Marshallian model cannot be sustained.
Without scarcity, this model of supply and demand is irrelevant. Like I said, you have it exactly backwards. What was your point again?