Yeah, the cartel thing was kind of a joke. It's actually extremely unethical and illegal in most places. You have to remember, the guy undercutting by massive amounts is probably trying to drive the market down so he can buy out and flip the products. If he pushes everyone down to 25% of market value, he's making 400% on the turn around.

You could just get in contact with your competitors and form a cartel. But even IRL cartels have a very limited life. Someone always ends up breaking the deal and undercutting everyone. Or push their prices down until you can buy them out and re-list for massive profits. Learn to play the market