You're arguing that a company with competition may choose to lower its price whether or not internal costs have lowered (or not). That's a different question entirely.
internal cost sets the lowest bar possible without a profit, it does not set what the price will be in the face of competition because companies charge as much as they can to maximize profit. That maximization either comes in the form of per-unit profit or volume profit.
I don't think anyone disagrees that companies must price their product competitively and that they seek profit, those are uncontroversial facts.
read the post again.
It's there, that you cannot see it is neither a damnation of the point, nor a refutation of it. If you cannot find a way to respond to the actual point being made there is no discussion to be had here.