"I didn't say I thought "everyone sells the same product at the same price." "
???Really??? Then perhaps you could tell us what this (from your post #693) means ...
"And why, exactly, would someone buy from you if your price was higher than the market price? Answer: they wouldn't. So you would lower your price until it matched the market price. "
It means there is a market price for whatever Principled is selling, even if he is selling something nobody else is. You can't charge $1,200 for your widget if people only think it's worth $1,000 - regardless of how unique it is.
You really might want to go to the bookstore and pick up a good, basic economics book.
"... you would lower your price until it matched the market price ... "
... doesn't mean you would lower your price until it matched the market price (e.g., sell at the same price)?? So you'd sell it at a different price despite the fact you saw fit to "... lower your price until it matched the market price ..."???
Sounds like you're saying exactly what you claim to not be saying - that you'd sell at the same price. And contradicting yourself to boot. The discussion wasn't about different products at all.
And thanx for the tip to your favorite book. You might also like this one:
Complete Idiot's Guide to Economics (The Complete Idiot's Guide).