The PayPal system wasn't designed for businesses. It was designed to provide a cheap way for the average person to transfer funds online and then they tried to form business models from the same mold - in my opinion, unsuccessfully. When all you have is a hammer, all your problems start to look like a nail. Thus, they rely on name recognition and volume rather then large fees. They don't encourage thier "business" models to allow users to merely submit information on the business website because they want users to have to visit their page. This, in addition to security concerns and their product restrictions (they don't allow the sale of many completely legal items such as software, certain firearms related products and many more) have been sufficient to cause me to look elsewhere for a payment option. I'll check out www.2checkout.com (no pun intended).
-Ben